Monthly Archives: October 2014

What Does Induced Demand Really Mean?

Suppose that New York City were to complete the Second Avenue Subway in 2015, and that in 2020, the line had hundreds of thousands of boardings per day, but the Lexington Av Line were still just as crowded. Would building the Second Avenue Subway be pointless? Or suppose we build a transit line through Sepulveda Pass, attracting hundreds of thousands of boardings per day, but traffic on the 405 doesn’t get any better. Would building the Sepulveda Pass transit line be pointless?

If our answer to those questions is “no”, then we need to think more critically about what it means for traffic to have remained the same on the 405 in the wake of the recent construction of the northbound HOV lane through the pass.

“Induced demand” is usually invoked to suggest the fruitlessness of widening freeways – if you add more lanes and traffic stays the same, why add more lanes? This misses the point. The whole reason you build transportation infrastructure is to move people and goods. Really, the opposite outcome is worse – what’s the point of building infrastructure if no one uses it?

Now, in the case of the 405, you might still argue that the money spent on widening the freeway should have been spent on a transit option instead. The project cost a billion dollars or so, which would be a pretty good down payment on Sepulveda Pass transit. I’m inclined to agree with you on that, but that’s a different argument than induced demand. And if building new freeway lanes through the pass doesn’t make traffic better, logically, neither will building transit. The question is just which project, freeway or transit, is a better investment.

Induced demand is an unhelpful concept. The phrasing makes it sound as if the construction of freeway lanes is what causes more traffic. But that’s not the case; the presence of development that people want to access, like housing, industry, commerce, entertainment and recreation, is what causes traffic. In other words, almost no one drives around on the freeway just to drive around on the freeway; they drive around on the freeway to get to some other place worth going to. When you build freeway lanes, you reduce the costs of traveling between places, so more trips will be made. The desire to travel was there before; the cost was just too high.

But wait, didn’t building transit, and later freeways, cause the growth of suburbs in the US? Well, sort of. If a transportation facility opens up access to development in new areas, you could say it induced its own traffic. But that’s not what people are usually talking about with induced demand, and it’s certainly not the case that widening the 405 was accompanied by a development boom. The Westside and Valley are constrained by zoning, not by the transportation network. If widening the 405 facilitated development anywhere, it would have to be distant places like Porter Ranch, Santa Clarita, and the Antelope Valley, but there hasn’t been a boom there either.

This is an important distinction. Billions of dollars have been wasted building freeways in rural America, in the hopes that the roads would induce demand, leading to economic growth. Likewise, many struggling cities have spent money on transit lines that have low ridership and have created little development.

In a large city, there’s almost always going to be trips that people want to make but don’t because of large travel times. This is especially true in large US cities, where we underprice road capacity to the point that new lanes are almost always quickly filled. We misinterpret the construction of the new lane as having caused the demand, but it was there all along.

We run into the same problem with zoning. Because we have constrained housing supply with zoning restrictions, any residential upzoning is usually followed by a boom in residential construction. We misinterpret the upzoning as having caused the boom, and think that we can cause other types of development, like manufacturing or other industry, by zoning for only those uses. But the upzoning didn’t cause the residential boom; the demand was there all along. So we end up with land zoned for industry sitting vacant or being put to low productivity uses.

What should we call it instead of induced demand? I think latent demand is more accurate, since the demand was there all along, waiting to be released. As an analogy, consider the latent heat of condensation. When air cools down, water vapor will condense into liquid water, releasing energy in the process. The cooling of the air didn’t create the energy; it just allowed it to be released.

So next time a transportation expansion is put to use right away, don’t call it induced demand, call it latent demand.

Advertisements

Comparing Transit Ridership and Roadway Volumes

This issue recently popped up on Twitter in a short conversation with @sandypsj.

One of the frustrating things about trying to put transit ridership into the context of total road use is that auto volumes and transit ridership usually aren’t reported in the same way.

When you look up traffic data, you get a point volume, usually the average number of cars passing a point on the roadway every day. Sometimes, you can also find the AM and PM peak hour volumes or peak 15-minute volumes in each direction, which are what traffic engineers use to time the traffic lights during periods of heaviest demand. When you look up transit ridership data, you usually get a total number of boardings for the entire line.

So, for the road you have the number of vehicles using only that segment, while for the transit line, you have everyone using any segment. For example, a daily count on Venice east of La Cienega showed 41,428 vehicles per day, while Metro ridership data shows 13,259 riders on Route 33 and 12,311 riders on Route 733, the bus routes serving Venice. If you assume an average vehicle occupancy of 1.2, that’s 49,713 people passing that point in cars. However, it’s not the case that (13,259 + 12,311)/(13,259 + 12,311 + 49,713) = 34% of all users on Venice east of La Cienega are using transit! Many 33 and 733 riders get on and off without going past La Cienega.

To figure out the proper comparison, you need to figure out the transit line volume for the same segment of roadway you have traffic volumes for. To do that, ideally, you need both boardings and alightings at each stop in each direction, perhaps even broken down by time of day. The number of boardings at each station is frequently available for rail lines, less often for bus lines. Data on alightings is not often available for rail or bus, though that’s slowly changing. For example, BART and the MBTA publish ridership data that includes not only boardings and alightings at each rail stop, but also each origin-destination pair. Since every boarding in one direction usually corresponds to an alighting at the same stop in the opposite direction, at a minimum you can get by with boardings at each stop in each direction.

For example, consider a hypothetical feeder bus route serving a rail transit station at Stop A, as shown below. There are ten stops, with the highest number of boardings at the transfer at Stop A, and secondary peaks in demand at Stops C and D, a subsidiary commercial node and transfer point.

hypothetical_route

We have boarding data in each direction at each stop. Since no alighting data is available, let’s assume alightings at each stop are equal to boardings in the opposite direction. We can therefore calculate the route volumes in each direction, i.e. the number of bus riders on each segment of the line in each direction, by setting up a simple table.

hypothetical_table

Northbound volume between Stops A and B is 2,000, since 2,000 riders board at Stop A and no one has had a chance to alight. At Stop B, 100 people board and 200 alight, so the route volume is 2,000 + 100 – 200 = 1,900. At Stop C, 800 board and 600 alight, so the route volume is 1,900 + 800 – 600 = 2,100, and so on. Southbound volumes are calculated the same way, by working up the column. Between Stops K and J, route volume is 400. At Stop J, 500 people board and 20, alight, so route volume is 400 + 500 – 20 = 880, and so on.

Note that because of our assumption about alightings, route volume in each direction is the same on each segment. Also note that the highest demand segment is between Stops C and D, not at the highest demand stop, Stop A. Lastly, note that while daily volumes are likely to be equal in each direction, demand throughout the day will probably be unbalanced. For example, since this is a feeder bus, we’d expect southbound volumes to be larger than northbound volumes in the morning, and vice versa in the afternoon.

Ok, now let’s suppose that daily traffic on the roadway segment between Stops D and E is 15,000 vehicles. Assuming an average occupancy of 1.2 passengers per car, that’s 18,000 people in cars. Therefore, between Stops D and E, the portion of total use being served by transit is 3,960/(18,000 + 3,960) = 18%. Note that if you compared total transit line boardings, 8,800, to the traffic volume between Stops D and E, you would significantly overestimate the portion of demand being met by transit. This example looks at daily demand; if you had traffic and transit data by the hour, you could do a more refined analysis.

It might be tempting to ignore this method, because it reveals the transit share to be smaller, but this is the right way to do the comparison. Frequent readers already know that this blog is certainly pro-transit, but also dedicated to honest analysis. When I present something, I want the backup to be airtight, so that transit opponents with ulterior motives can’t shoot it down on technical merit.

Case Study: the 24, the 680, the 242, and the 4 Compared to BART’s Bay Point Line

Twitter user @asmallteapot brought up the Caldecott Tunnel and BART’s Bay Point Line as a potential comparison between transit ridership and freeway volumes. Features like the Caldecott Tunnel offer particularly good reference points, since the tunnel creates a bottleneck where the only two options serving those trips are the freeway and the transit line.

BART provides full origin-destination ridership data, and Caltrans has good freeway volume data. In this example, we’ll compare the BART Bay Point Line between Rockridge and Pittsburg/Bay Point to the competing freeways, the 24, the 680, the 242, and the 4. The comparison between the 24 through the Caldecott Tunnel and BART between Rockridge and Orinda will be most accurate; for the rest of the line there are other alternatives that we can’t account for. This is especially true from Walnut Creek east, where the freeways are also serving trips not in competition with BART.

Here’s the origin-destination data, simplified to look at only the Bay Point Line from the Caldecott Tunnel east. Blue shading indicates westbound trips; red shading indicates eastbound trips.

BART_OD

Here’s the data tabulated into westbound and eastbound volumes, along with comparison to the appropriate freeway segment and BART mode share (assuming 1.2 passengers per car). As you can see, there’s little difference between the volumes in each direction. If we’d only had directional boardings, and assumed alightings equal boardings in the opposite direction, the results would be about the same.

click to embiggen

click to embiggen

Through the Caldecott Tunnel, BART is handling about 26% of total demand – not bad at all considering the fairly crappy off-peak headways and the fact that the freeway has four tunnels to BART’s one.

In the past, recording and compiling detailed boarding and alighting data would have been an inordinately time-consuming task, but with modern fare cards and automatic passenger counter technology, it should be quite easy, even in 15-minute intervals or at the individual vehicle level. Hopefully, more agencies will make this data available so that planners and activists can put it to good use.

Mini-Case Study on Mega-Project Management

When people think about mega-projects in Boston, the Big Dig, along with its enormous cost overruns and construction quality issues, is what comes to mind. But there’s another Boston mega-project that started at about the same time, and didn’t become an archetype for infrastructure incompetence: the Boston Harbor clean up.

In the 1980s, due to decades of pollution from poorly-treated sewage and combined sewer overflows, Boston Harbor was a stinking embarrassment. A lawsuit under the Clean Water Act resulted in the state being forced to improve stormwater and sewage treatment systems so that water quality in the harbor would recover. It’s a little surprising that there doesn’t seem to be a detailed study comparing the two projects; because both projects were constructed at about the same time in the same city, there should be less issue correcting for exogenous factors like legal precedents, quality of local contractors and engineering consultants, and political institutions.

However, a trio of articles from the fall of 2006 offers some insight. A short article in Governing cites three major factors: continuity of oversight leadership, local funding, and in-house talent at the Massachusetts Water Resources Authority (MWRA), the agency created in 1985 to oversee construction and operations of the sewer treatment system. Continuity of leadership came in the form of oversight from the same federal judge and several long-serving MWRA board members, while the use of local funds for construction created an external incentive to control costs. Inside the MWRA, a small team of talented engineers oversaw the contractors and consultants, providing strong owner representation.

In a Commonwealth Magazine expert panel on the Big Dig, Douglas McDonald, who served as Executive Director of the MWRA for nine years, cites the MWRA board of directors as the critical difference between the two projects. According to McDonald, the Executive Director had to report to the board of directors and a community advisory board every month, answering questions in real time. In contrast, leadership at the Massachusetts Turnpike Authority, which managed the Big Dig, saw more frequent turnover and political interference. McDonald says that “it’s not totally clear to whom the Bechtel corporation [which oversaw the Big Dig] ever reported.”

Lastly, in a long-form article looking at the mismanagement of the Big Dig, Boston Magazine cites the high level of in-house talent at the MWRA as the critical factor. The article quotes David Luberoff of Harvard’s JFK School of Government saying “it’s clear the state needed to have someone with Bechtel’s expertise, but the state could have done a better job of managing the managers. You have to have a small, highly skilled, highly respected group of people who could look over Bechtel’s shoulders.” In other words, a project as unique as the Big Dig is always going to be beyond the capabilities of the managing public agency, and there’s nothing inherently wrong about using outside consultants. However, strong advocacy on the owner’s part is still required.

The article goes on to quote Paul Levy, another former MWRA director, saying that “we had a 50-person project management team within the MWRA of highly paid, very experienced people… right after I hired Dick Fox, I remember [Big Dig architect and former Secretary of Transportation] Fred Salvucci calling to congratulate me, saying he wished he could do that but it was not possible under the state personnel system.” Thus, it appears that a political decision – subjecting the DOT to the state’s personnel system but exempting the MWRA – made it more difficult for the Big Dig to hire people with the skills required to oversee the project. The inability to pay wages that are competitive with the private sector is a pervasive problem for public agencies.

Readers with experience in private land development will not be surprised by any of this. As a land developer, you need to hire a team of consultants to successfully complete a large project, including legal professionals, civil engineers, architects, mechanical-electrical-plumbing consultants, structural engineers, construction contractors, and construction managers. While they are all on your payroll, they all have other interests as well, which may conflict with your priorities. Architects will select more elaborate designs and finishes, both out of professional pride and the desire to have future clients see a portfolio of high-quality work. Civil engineers don’t want to aggravate the public agencies they interact with for other projects. Construction managers don’t want the contractor community to see them as too adversarial. Contractors might be losing money on another project and looking to make up that loss on other jobs. As an owner, you must strongly advocate for your interests and priorities. If you’re asleep at the switch, you’ll end up paying too much for the job, even if the entire project team is working ethically and there are no serious issues.

The harbor cleanup project was not without issue. For example, in 1999, two workers died near the end of the project’s nine-mile long tunnel due to a failure of the improvised breathing systems that they were using. However, the project was successful in its water quality goals; today you can swim at Spectacle Island, something that would have been unthinkable in the 1980s. The MWRA seems to be one of the more respected state agencies.

Meanwhile, the problems with the Big Dig have poisoned the public debate on transportation mega-projects. People now expect that the projects will be poorly built and have massive cost overruns, which makes it much more difficult to build political support. Progressives that think cost effectiveness and public trust don’t matter, take note.

Eliminating Loop Ramps: The 10 at La Cienega and La Brea

In this introductory post on urban freeway improvements, the elimination of loop ramps and slip ramps was identified as some of the lowest-hanging fruit. It’s relatively cheap to do, and it makes things much better for bikes and pedestrians by getting rid of long, skewed crosswalks and road geometry that encourages drivers to speed. Since loops take up a lot of real estate, it also frees up a decent amount of land for development. Inspired by a recent comment, here’s a look at two interchanges on the 10: La Cienega and La Brea.

La Cienega

The westbound ramps at La Cienega are already in a tight diamond configuration, so there’s nothing to change there. The eastbound ramps are in a cloverleaf configuration, albeit a modified one, since Venice cuts through the vicinity. Thus, the northbound La Cienega on ramp to the 10 eastbound is a right on Venice, then a right on the ramp. The loops are very tight, with curve radii down in the neighborhood of 80’.

The basic idea here would be to remake the eastbound ramps in the image of the westbound ones. The interchange would become a modified tight diamond, with a new road connecting the two ramps between La Cienega and Venice. This would reconfigure the free movements to and from the ramps into normal city intersections, making them less hazardous for pedestrians and bikes. It would also yield new signalized pedestrian crossings of La Cienega and Venice, making things a little more walkable.

the10-LaCienega

click to embiggen

This concept uses 10’ lanes and 6’ curbside bike lanes on La Cienega. Now, I know what you’re thinking – why is there no crosswalk on the north side of the intersection of the new ramps and La Cienega? Three-legged pedestrian crossings are horrible! The reasoning is that adding a crosswalk there makes things considerably harder for the traffic engineering, and this location is a rare exception to the rule that you should never omit a crosswalk. Because there’s nothing on either side of La Cienega on that side of the ramps, there’s no chance a pedestrian would have to use all three crosswalks in lieu of the missing crosswalk. Anybody walking here is going to either a destination north of the 10, in which case they can cross at David Ave and the onramp to the 10 westbound, or a destination south of the new ramps, in which case they can cross on the south side of the intersection.

This concept adds two lanes under the freeway bridge. It looks like this might just fit under the existing bridge, because the east side has a row of parking between the existing edge of pavement and the columns.

On the traffic side, the loop ramps are both serving over 10,000 vehicles per day. Those turning movements, which are currently free (unsignalized) right turns, will be replaced with left turn phases at the new traffic signal. Excluding the crosswalk on the north side of the intersection makes that left turn easier, reducing the green time needed for the eastbound movement. Again, this is only acceptable because it’s a special situation. Here are the traffic volumes at the new intersection.

LaCienega-table1 LaCienega-table2 LaCienega-sketch

Traffic volumes are from Caltrans and LADOT. This is a really rough estimate. The approach was to guess at the worst conflict group (combination of movements that can’t proceed at the same time) for each intersection, and figure out the sum of capacities needed for each movement in the group. That’s the “g/C” column (green time divided by cycle time), representing the percentage of the total intersection capacity needed for that movement. For example, the left turn from the 10 eastbound to La Cienega northbound needs 23% of the capacity at the intersection. If the total of that column is greater than 100%, or even relatively close, the intersection is close to failing.

La Brea

The existing interchange at La Brea is a full cloverleaf, with loops almost as tight as 100’ radius. However, the interchange doesn’t function like a true cloverleaf, because the outer ramps have very sharp cure radii to and from La Brea, and the offramps using the outer ramps have traffic lights instead of free-flowing turns.

The plan at La Brea would be to reconfigure the interchange as a tight diamond, using the same parameters – 10’ lanes, 6’ bike lanes. There are two options, one with the ramps tight up against the freeway, and one with the ramps intersecting La Brea near where the outer ramps do today.

the10-LaBrea-1

click to embiggen

the10-LaBrea-2

it’s a perfectly cromulent word

The advantage of the first option is that it lets you do the same crosswalk trick as at La Brea. However, unlike at La Cienega, there’s no extra room under the freeway at La Brea. We can steal the weaving lane to get four lanes under the bridge, but that leaves only a single lane for the left turns onto the 10. Unfortunately, that probably won’t work on the traffic side.

By pushing the ramps further away from the bridge, the second option lets you fit in a second left turn lane, though due to the lane’s short length, it might be a little optimistic to assume it could be used to its full capacity. Also, because the second option puts the new development between the ramp intersections, it’s no longer acceptable to omit a crosswalk. That makes the traffic design more challenging.

Traffic volumes on La Brea are daunting – the road serves nearly 70,000 vehicles per day here, more than many freeways that are two lanes per direction. The heaviest ramp volumes are to and from the east, all approaching 10,000 vehicles per day.

LaBrea-table1 LaBrea-table2 LaBrea-sketch

This design would require the crosswalks closest to the freeway to be concurrent with the left turns from the freeway offramps, which might be difficult given the traffic volumes.

Palmer Paradise

Now normally this is the part of the post where I’d suggest auctioning off the real estate to the highest bidder, as long as they agree to do something with it other than surface parking. That way you don’t end up with prime real estate owned by the government sitting vacant for years because it was impossible to come to a consensus on what to do with the land.

But you know what? F!@# it. These freeway-adjacent sites are right in GH Palmer’s wheelhouse. Just dial him up and let’s get us a few hundred Italianate apartments built. We can call them The Palude and The Catrame (the Italian equivalent of La Cienega and La Brea).

Traffic Troubles

While the idea of improving these interchanges for pedestrians and bikes, and freeing up space for urban development, is appealing, the worst g/C ratios approach 1 at both interchanges. More traffic study would certainly be required to see if these plans are viable.

Politically, any plan to eliminate loop ramps is going to have to win the support, or at least the grudging tolerance, of drivers. Unfortunately, these interchanges are not the best candidates for the first project, because if the first project doesn’t go well, there won’t be any more. Back to the lab again. . .

 The sausage-making behind this rough traffic analysis: I assumed the ramp volumes have the same peaking as the through movements on the 10, and 1,700 veh/hr capacity for each lane at the intersections. The critical conflict group at La Cienega was assumed to be Offramp EB – La Cienega NB – La Cienega SB left turn. At Venice, Onramp EB (from the La Cienega SB left turn) – Venice EB – Venice WB left turn. No volume was available for the last movement so it was a wild guess. The critical conflict groups at La Brea were assumed to be Offramp EB – La Brea NB – La Brea SB left turn, and Offramp WB – La Brea SB – La Brea NB left turn.

Should Streetcar Skeptics Stick a Sock In It?

Ok, to be fair, that’s not what Dave Alpert said in his Citylab piece today, but once I thought of that title, I couldn’t resist.

The article says that mixed-traffic streetcar skeptics shouldn’t be so quick to denounce the projects – “don’t let the perfect be the enemy of the good” – for five reasons: imperfect transit can still be good, limited funding makes the perfect unachievable, funding won’t get redirected towards better projects, streetcars have higher capacity than buses, and improvements can always be made in the future.

There are some larger things in play here, but first, let’s take a look at the idea of imperfect projects in general, and the five reasons offered.

An Imperfect Project Isn’t Necessarily Good

No transit project is perfect. For example, consider LA’s Expo Line. In my humble opinion, some of the stops weren’t needed – Farmdale and perhaps Expo Park/USC. All riders would agree that the Flower Street Crawl, as we call the unacceptably slow portion of the line from Jefferson/USC to the Blue Line Junction, needs improvements to make it run faster. And penny-pinching value engineers can find plenty to gripe about, like the use of low-profile catenary, the unnecessary lights mounted on OCS poles, or four-quadrant highway crossing gates with four independent pedestrian gates.

Yet on the balance, the Expo Line is still a really good project. It provides a transit service that is competitive with the freeway and arterial road alternatives, and connects several existing dense nodes of development. The Expo Line and Blue Line have some of the best new LRT ridership in the country, despite an appalling lack of upzoning.

The proposed downtown LA streetcar, on the other hand, is a very weak project, regardless of mode. It’s a one-way loop that partly duplicates existing services that are far superior. Even if it were completely grade separated, it wouldn’t be any better than underutilized downtown people movers in places like Detroit and Miami. Opposition to the streetcar isn’t just based on it being mixed-traffic, it’s that even a technically perfect project on that corridor would not be a good project from a transit planning perspective.

In general, streetcar proponents seem to discount the idea that streetcars could be bad for transit, but that possibility must be considered. A project that requires heavy operating subsidies can drain service away from other transit, like buses. Many transit advocates in Austin point to the heavily subsidized Red Line rail for causing cuts to bus service, and fear that a poorly planned Project Connect will make things worse. Even LA’s rail transit projects, which perform very well on ridership, come under fire from bus advocates like the Bus Riders’ Union, which alleges that transit dependent populations have lost bus service in order to fund rail. If you’ve ever ridden a full 204 bus down Vermont in the evening, when it’s running 20 minute headways, and transferred to a relatively uncrowded Expo Line running 10 minute headways, you can see where that perception comes from.

If you build projects that make existing transit services worse, you run the risk of losing riders, and alienating part of the political base that supports transit.

Increasing Urban Development

The Citylab post suggests an imperfect streetcar might be acceptable as a way to increase the supply of walkable, urban places, but this is not a good reason to build a transit project. If there is desire for urban neighborhoods, they will be built if zoning allows for it. Upzoning along the Expo Line would likely lead to a boom in dense residential construction on LA’s Westside, but that development would happen with upzoning even if the train wasn’t there. Where development does follow streetcars, like Portland’s Pearl District, it has been awarded large tax subsidies.

Funding is Limited

Federal funding for transit is scarce. Metropolitan regions compete with each other, and within each region, there are competing projects. This results in reductions to project scope, to try to be able to build the project for less money, or in phasing projects, to spread out costs over time as funding becomes available. For example, the Purple Line to Westwood would be better off being built as one contract, in one phase, avoiding the need to issue multiple procurement packages and the cost of mobilizing and demobilizing several times. However, Measure R funds aren’t available fast enough, so the project is split into three phases.

On the other hand, the project needs to be big enough and useful enough to make sense as a standalone job. You couldn’t build a suspension bridge with only one tower, and you probably wouldn’t build a mile of Purple Line tunnel with no stations just because that’s all you had funding for. If you can’t meet a minimum threshold of utility, you’re better off not building the project.

Funding Won’t Get Redistributed to Better Projects

This is misdirection. It’s certainly true that, due to political constraints, money can’t be shifted easily to better projects. However, that doesn’t answer the question of the usefulness of the project at hand. As Alpert points out, it’s possible that the WMATA Silver Line money could have been spent on better projects, but the Silver Line is a good project on its own. Likewise, the Westside Subway is logically the highest priority subway in LA, but the Red Line to North Hollywood got built first because of political reasons. Fortunately, the Red Line is still an incredibly useful project on its own merits.

Streetcar Capacity

Streetcar proponents often point out that streetcars have higher capacity, and therefore theoretically lower operating costs, than buses. This is only true if you’re serving a high-demand corridor, where using streetcars would allow you to save a lot of money on driver labor. Streetcar routes that are running service every 15 minutes, or even less frequently, are clearly not at the point where bus capacity is saturated. This is a guess, but I think if you have hit the point where mixed-traffic buses are inadequate to serve the demand, or where rail would offer significant operations savings, you’re probably at the point where you need exclusive lanes as well.

Future Improvements

The prospect of future improvements is a legitimate reason for accepting an imperfect project, so long as the project is set up to enable those improvements. Alpert uses single-tracking a rail line and shorter platforms as examples, and they’re good ones. LA’s Blue Line was also built with two-car platforms, later extended to three cars to accommodate high ridership.

The challenge with mixed-traffic streetcars, especially if they’re curb-running, is that they don’t easily lend themselves to future improvements. Converting curb lanes to exclusive lanes is more difficult than converting center lanes because of drainage issues, parking, and driveways. The latter, in particular, can make it difficult to extend a sidewalk platform to accommodate longer vehicles in a dense urban environment. Short downtown lines are often pitched as “starter lines”, but long lines are not workable at the speeds achieved by curb-running mixed-traffic streetcars.

Context

There are, of course, more than enough highway boondoggles to put things in context. You could also compare streetcars to, say, Essential Air Service subsidies, which blow millions of dollars subsidizing air travel to small cities across the country. Those are good points, but public opinion is remarkably adept at compartmentalizing government waste. Rob Ford can blast city councilors for getting free zoo passes, then turn around and propose wasting billions on converting Scarborough RT to a subway. Again, projects have to be worth it on their own merits, rather than being excused by something worse.

Note that none of this should be taken to mean that streetcars are always a bad idea. The Columbia Pike project is frequently cited by streetcar proponents, and it has the potential to be a good project. For starters, it’s a straight, logical route, and they’re proposing to run 6 minute headways, which suggests existing transit demand is high enough that rail might be cost effective for operations. If it were center-running, it would offer the potential for future improvements that might lead some technically inclined observers to support it.

The Big Picture

In the big picture, the streetcar debate is part of the ongoing rift between what Alon Levy called politicals and technicals. Progressive political activists are inclined to view any expansion of rail transit services as a positive, building towards a future where there is more political support for transit expansion. Technical commenters are inclined to believe that you can only build so many bad projects before the people realize their money is being wasted.

This blog is LA-centric and written from an engineering perspective, naturally tending toward the technical side. Simply put, if the Blue Line and Red Line were running empty trains all day long, I do not think we would be building the Expo Line and Purple Line. While I understand the need to build political constituencies to support policy changes, I also think nothing succeeds like success. LA voters are demanding an expansion of rail transit services, while residents of greater Portland are pushing back against further expansions of streetcar and LRT service, putting higher priority on more frequent bus service.

Alpert’s piece concludes with a warning that “writers who think more transit is good for cities should bear in mind that not all readers necessarily agree with that basic premise”, referring to opponents who don’t want to fund transit at all. This statement is similar to Robert Cruickshank arguing that because some ideological transit opponents use efficiency as a false flag attack, progressives should actively shun the idea that efficiency matters.

Well, guess what – I don’t think more transit is necessarily good for cities! Resources are limited. Transit that is grossly inefficient, or wastes capital dollars, is not good for cities. This is a fundamental failure of allies for good transit projects to understand where their fellow advocates are coming from. But as frustrating as it may be at times, we ultimately need each other’s support. Political advocates need to learn what projects will gain long-term support by providing useful services, and technical advocates need to figure out how to improve public understanding of what makes transit useful.

And if the project is just to support condo developers, well, let them build it.