Tag Archives: Pedestrian crossing

Leading Walk, Lagging Arrow

One of the easiest things you can do to help out pedestrians is the leading walk indication. At a normal traffic light, the pedestrian light turns to “walk” at the same time the signal head for cars turns green. This tends to lead to drivers trying to jump the light and turn right before the light turns green, cutting right in front of pedestrians as they start to cross the street – an experience you’ve surely had if you spend any time in downtown LA.

With a leading walk, the pedestrian light turns to “walk” a second or two before the signal for cars turns green. The idea here is that pedestrians get a chance to start crossing the street before the cars move, so drivers don’t get a chance to cut them off. This is really what’s supposed to happen anyway; we’re just tweaking the light to nudge people in the right direction. Obviously, this works even better if you have no right turn on red – something that’s appropriate during the day in a place like downtown LA where you have heavy pedestrian volumes. This arrangement is common in many places that have made a point to prioritize pedestrian movements, such as Cambridge, MA.

However, a problem can arise with this arrangement. If pedestrian volumes are very high, the crosswalk never clears, and it becomes very difficult for traffic to make turns. This decreases the capacity of the intersection and causes congestion, which is bad news for buses and emergency vehicles too.

The solution to this problem, if it arises, is hinted at by several lights around downtown LA that have a right turn arrow that comes up after the “flashing don’t walk” ends. This ensures some turning traffic gets to proceed during every light cycle, though it requires the pedestrian phase to be shorter than the maximum possible. A trade-off here might be to add some bulb outs at the intersection to increase the width of the sidewalks and crosswalks. While capacity of pedestrian facilities isn’t usually an issue, in this situation it might be, and this change would help improve pedestrian flow.

Freeway Ramps and Crosswalks

We haven’t had a freeway post in a long time, but a while back we talked about short-term improvements that can improve the interface between freeways and city streets for pedestrians and bicyclists. The principle goal is to reset drivers’ minds for the urban environment by forcing them to slow down or stop when exiting the freeway, so that they don’t hit city streets at freeway speeds. The best designs for this are the tight diamond and the tight four-ramp partial cloverleaf.

Ideally, we’d like to also strengthen pedestrian connections by providing crosswalks on the city street that would run concurrent with the freeway off-ramp. The city street is often a major arterial road where the crosswalk spacing is too large, and a crosswalk at the ramp would help alleviate that problem.


Here are two locations where such crosswalks were actually installed.

First, the 134 and Glendale Ave:

Second, the 134 and Pacific St:

Nice work, Glendale, on getting those tight diamonds, tight four-ramp partial cloverleaves, and extra crosswalks!

However, freeway ramps are not great locations for crosswalks. At most intersections, the majority of traffic goes straight, with smaller turning volumes, making it feasible to have concurrent pedestrian movements without much danger to pedestrians or impact to traffic capacity. At freeway ramps, though, the situation is reversed. Almost all traffic is turning, so concurrent pedestrian movements create danger to pedestrians and significantly reduce traffic capacity. While pedestrian safety can be improved at such intersections with a leading pedestrian interval, the other problems remain.

Fortunately, there’s a way around this issue that improves pedestrian connections, has a low impact on traffic capacity, and serves the goal of forcing drivers to adjust to city driving conditions. We can simply move the ramp crosswalks away from the freeway, and synchronize the traffic lights so that the crosswalk movement is concurrent with the ramps.


This creates space for the traffic exiting the freeway to queue up. Since drivers exiting the freeway will always encounter a red light at the crosswalk, they will be forced to stop and reset their minds. Pedestrians do not have to contend with conflicting traffic, and the location of the crosswalk might better serve them. A crosswalk adjacent to a freeway will be located such that the freeway is occupying much of the nearby street frontage, whereas a crosswalk further away will serve more development.

If there’s an unsignalled minor street nearby, that’s a natural location for a new traffic signal and the crosswalk. Let’s look at a few examples around the county.

The 134 & Pacific in Glendale:


The 10 & Normandie in LA:


The 405 & Artesia in Torrance:


The 405 & Western in Torrance/LA:


These improvements obviously require new traffic signals, which is a considerable expense. Therefore, they should be rolled into either freeway improvement projects or arterial corridor improvements. The pedestrian signal is only a simple two-phase signal, and doesn’t need much intelligence since it will be synchronized with the ramp, which will help some with costs, especially if part of a larger job.

When Do Pedestrian Grade Separations Make Sense?

Metro just approved a budget increase for the proposed pedestrian bridge across Lankershim and Universal Hollywood Drive at the Universal City Red Line station, bringing the total to $27.3 million (including $1.4 million diverted from Rail Preventative Maintenance – nice touch). Now to be fair, a lot of the cost of the pedestrian bridge is going to be in the three elevators. This is machinery that has to (a) cycle reliably hundreds of times every day, (b) hold up under exposure to the weather and the, um, indiscretions of the public, and (c) incorporate transparent materials so that it doesn’t attract crime.

But that’s not really the point. The bridge, or an equivalent tunnel, is a questionable expenditure because many people aren’t going to want to use it anyway. I’ll outsource that argument to Damien Newton over at Streetsblog, and move on to the general question of when pedestrian grade separations make sense.

It’s All About Destinations

Fundamentally, a pedestrian grade separation makes sense if it connects to strong destinations on both sides at the same elevation as the grade separation.

When I lived in Boston, I explained this using a simple comparison of three pedestrian grade separations in the city. The first is the bridge between the Prudential Center and Copley Place, crossing Huntington Av:

Everybody in Boston knows this bridge. On the left is the Prudential Center mall, office towers, and residences. On the right is the Copley Place mall and hotels. The main levels of these malls are at the same elevation as the pedestrian bridge, so if you’re crossing, the bridge is actually more convenient than going down to street level and back up. Note, though, that this doesn’t alleviate the need for crosswalks at street level, because it’s still unreasonable to expect people on the street to go up, over, and down to cross, so there are still crosswalks on Huntington.

The second is the underpass from Back Bay Station on the Orange Line to Copley Place, going under Dartmouth St. Most people know this underpass and have used it. It’s at the same elevation as the Back Bay Station subway platform, so it’s useful to connect to that. On the Copley Place side, there’s nothing that low; everything is at least one floor up. If you’re just crossing Dartmouth St, or going from Copley Place to the commuter rail, you’re not going to use this underpass.

The last location is the underpass at Mass Av Station on the Orange Line. Many people, even those who live or work in the area, don’t even know this underpass exists. On the south side, it connects to the subway mezzanine. On the north side, it connects to nothing; you have to go up to the street. The result is that no one uses this grade separation. As a result, at both Dartmouth St and Mass Av, the city ended up going back 20 years later and putting in crosswalks at the street level anyway.

Mass Av:

Dartmouth St:

Crosswalks Make Sense, Even at High Traffic Locations

If you want a comparison to Lankershim, Universal Hollywood Drive, and Campo de Cahuenga, you could take the case of the Leverett Circle pedestrian bridge in Boston. This bridge connected the sidewalks on opposite sides of O’Brien Highway and Storrow Drive, and the mezzanine of the elevated Science Park Green Line Station. These are high volume roadways (Storrow is almost a freeway), and there are ramps to the 93 freeway at this intersection – not unlike the heavy traffic on Lankershim and Campo de Cahuenga, and the ramps to the 101.

During construction for the Big Dig, parts of the bridge had to be demolished and replaced with temporary structures, and some pedestrian movements were provided with crosswalks. The plan was that when construction was complete, the pedestrian bridge would be rebuilt and the crosswalks eliminated. However, walking advocates in the city gained strength, and the Big Dig went ruinously and comically over budget. The reconstruction of the bridge was therefore cut from the project – it was a pedestrian facility that walking advocates didn’t want, and the project couldn’t afford to build.

Today, all legs of the intersection have crosswalks, and it’s a much more pleasant environment without the overhead bridges. This area gets a ton of pedestrian traffic, since it’s part of the recreation paths along the Charles River.

Back to Universal

With these lessons in mind, it’s pretty easy to see that Damien Newton is spot-on about the Universal City pedestrian bridge. No one is going to want to go up, over, and down. A tunnel would be a little better, because at least it would attract people going to or from the subway station, but it wouldn’t obviate the need for crosswalks on all legs of the intersection. Maybe I’m being overly optimistic about the rationality of the players involved, but hopefully the city can sit down with NBC Universal, explain these things, and figure out a better way to spend money on improvements here.

Downtown LA Skyways

We can also see the same factors in play in downtown LA, with the pedestrian bridges built along with all the “new downtown” skyscrapers like the Bonaventure. Since many of the buildings have active uses on the same levels as the bridges, they do see a reasonable amount of use, but they obviously don’t eliminate the need for crosswalks at street level. They’re also pretty cool for filming Batman scenes, so they have that going for them.

Downtown LA Pedestrian Tunnels?

One place I do think we have some potential for pedestrian grade separations is for pedestrian tunnels in downtown LA. For example, the owners of Macy’s Plaza recently announced their intent to connect the underground mall in their building directly to the 7th/Flower subway station. This is a new concept for LA, but it’s common in places like Seoul, where developers seem to really understand the value in having a direct connection from a busy subway station to their retail areas.

At 7th/Flower, I can think of two additional potential connections that might make sense.

The first is a no brainer. There’s a big hole in the ground right now at 7th and Figueroa, literally right across the street from the Figueroa entrance to 7th/Flower station. I’m not sure exactly what Korean Air has in mind for their subterranean levels, but if you’re building a 70-story building, the cost to build a hallway underneath Figueroa to connect to the subway station isn’t that bad. If they’re considering street level or underground retail, this would add value to their project.

The second is a little tougher, and might require cooperation among public agencies and several different private owners. Thomas Properties, which owns the block bounded by 5th, Flower, 6th, and Figueroa, is currently sitting on some vacant space in their underground mall. This retail center might benefit from a direct connection to 7th/Flower too. (Earlier concepts for the Regional Connector had a station right at the mall at 5th and Flower, but that’s just way too close to 7th/Flower and 2nd/Hope.)

Getting to that property would be considerably more difficult. The existing Blue Line tunnel, to be extended by the Regional Connector, ends just south of 6th. Building a separate walkway would probably be cheaper than rebuilding and widening the Blue Line tunnel here. Going under the sidewalk would mean interfering with a lot of utilities and foundation tiebacks.


Maybe – and it’s a big maybe – you could do something by redeveloping the two-story building on the NW corner of 7th and Flower, and providing an integral headhouse that would connect to the existing Flower St mezzanine level. From there north to 5th, you’d go through the basements of the existing buildings, which could be redeveloped. A concept like this would depend enormously on the types of foundations, relative elevations of basement levels, location of underground parking ramps and building machinery, and so on, not to mention the willingness of different private property owners to cooperate with each other. But it’s an intriguing concept to have in the back of your head, anyway.

Back to Universal Part II

Idle speculation about downtown aside, I just don’t see the point of a bridge at Lankershim. Prohibiting people from crossing the street at-grade, as was suggested at the Metro board meeting, is even worse. In general, people are going to walk where they need to walk – they’re not going to make huge detours like going over ped bridges or taking three crosswalks because you avoided putting one in so that you could gap out a signal phase a few seconds earlier. Design that doesn’t address the city the way people actually use it is bound to result in unpleasant streets and dangerous conditions.

Random Thoughts on La Cienega

So the other day, I found myself walking on La Cienega between La Cienega/Jefferson Station and the corner of La Cienega and Washington.


This area is surprisingly industrial, which makes walking on the west side of La Cienega a little bland – there’s just not a lot there. We’re not talking about the huge factories or distribution warehouses you find in the IE; this is all small scale industry – small businesses and workshops. I have no problem with urban industrial districts, quite the opposite; for example, in my post on the Union Station area, I noted that progressives have a weird proclivity for waxing nostalgic about well-paying industrial jobs in theory, and regulating them out of existence in practice. From a selfish point of view, the world would be a little less magical if I didn’t get to smell See’s Candies making chocolates from the Expo Line when the wind blows the right way.

Industrial uses, by their very nature, have a high ratio of square footage to employees. If the west side of La Cienega is industrial, it’s kind of a border vacuum, so the east side really needs to pick up the slack. The blob of SFR zoning between La Cienega and Clyde (in yellow) really doesn’t help in that regard. The areas that look like they’re zoned for multi-family (in orange) are mostly zone RD1.5 and RD2, which require 1,500 SF and 2,000 SF of lot area per unit, making them relatively low density. Really, there shouldn’t be any zoning this light on the Westside.


For its part, Culver City has both sides of La Cienega zoned industrial, and the residential neighborhood to the west is zoned Two-Family Residential, which only allows SFRs and duplexes. Again, this is ridiculously low for the Westside.


But really, I wanted to write about two specific locations on La Cienega, not general land-use (hey, I said this was a random post).

La Cienega and Fairfax

This first one should be uncontroversial. If you’re walking on the east side of La Cienega (the more interesting side to walk on), there’s no crosswalk for you at Fairfax.


This means that in practice, if you wanted to be safe, you’d have to detour all the way to Adams.


I’m aware that legally, there’s an “unmarked crosswalk” at Fairfax (as well as crossing Fairfax at Smiley and Perry). But let’s be real here. None of those locations have curb cuts. Crossing Fairfax at an unmarked crosswalk is dangerous, and probably nearly impossible at rush hour. It was Saturday morning, so my friend and I dashed across during a gap in traffic, but I wouldn’t want that to part of my day on a regular basis.

What’s really weird here is that at the signalized part of the intersection, they give you a crosswalk and pedestrian lights to cross to the traffic island – a place that, once you’re there, you have nowhere to go but back where you came. The problem for pedestrians on La Cienega could be fixed relatively easily: just add a repeater off the signal heads for La Cienega northbound on the ramp to Fairfax northbound. When La Cienega northbound is red, turn that light red too, and let people cross. There’s no need to add a new phase to the signal. Just a couple hundred feet of trench, a mast arm, two ped signal heads, and maybe three traffic signal heads. With luck, there’s spare room in the lamp drivers. I’d even accept a beg button here to placate traffic concerns (ped volumes are pretty low, but check out the Google Street view if you think no one walks here).


Now the other issue is less obvious: if you’re walking south on the east side of Fairfax, and you want to cross to the west side of La Cienega, this is a very roundabout path. Same goes for walking north on the west side of La Cienega and wanting to get to the east side of Fairfax.


You could still solve this without changing the signal timing. Drop another crosswalk on Fairfax, with the signals showing the same thing as the ones at the first crosswalk. Add a crosswalk on La Cienega on the south side of Fairfax, which would run concurrently with the signal phase for Blackwelder. This one would require a beg button; I think the phase for Blackwelder is actuated (i.e. only comes up when a car is on the detector). This one might require some new hardware in the case.


A longer term option would be to eliminate the high-speed geometry for the turn onto Fairfax, and tighten that move up into the main intersection. That would free up some space for a pocket park.

La Cienega/Jefferson Bus Loop

This idea will probably be a little less popular, and I’m not sure about it, but I’ll throw it out there anyway.

When the Expo Line was built, the La Cienega/Jefferson station got a 5-story parking garage on the southeast side and a bus loop off of Jefferson on the east side. The connecting bus services are routes 38, 105, 217, 705, and Culver City 4. The 105, 705, and Culver City 4 are just passing by on La Cienega, so in the interest of not delaying through passengers, we don’t want them to turn into the bus loop – they should just stop on La Cienega. The 38 runs from the Washington/Fairfax transit hub to downtown via Jefferson – a route not much different from Expo Line itself, and I wouldn’t expect many transfers. Turning into the loop would be trivial but unnecessary for the 38 eastbound, but would cause delays for the 38 westbound.

The only service for which using the loop really makes sense is the 217, because many trips originate or terminate at La Cienega/Jefferson, and it’s a time point for the route. The 217 never runs headways less than 12 minutes, so the traffic light for the bus loop is really only going to be used by 5 vehicles per hour.

On the other hand, the driveways for the parking garage are unsignalized, so your only option is to turn right onto La Cienega northbound or Jefferson eastbound. The former is fine, but pretty much no one wants to go east on Jefferson – they just came from downtown and probably want to go west on Jefferson or south on La Cienega. Want proof? Go hang out there in the afternoon, and watch how many cars come out and flip a u-turn in the middle of Jefferson. With minimal onsite work, the garage driveway could be reconfigured to use the bus loop traffic light so that traffic can turn left (there’s no current aerials, you’ll have to take my word for it).

A lot of people are probably not happy that the garage was built in the first place. The 476 parking spaces provided probably added something in the vicinity of $10-12 million to the cost of Expo Phase 1. To recover that cost, even with generous assumptions (5% interest rate, 50-year return period, each spot used 330 days a year), you’d have to charge over $4 per day for parking. Currently, the garage is pretty full, so it is being used, but Metro is giving the parking away for free. It’s unfair to subsidize parking for people who can afford a car, considering that the median income of LACMTA rail riders is about $26k and 55% don’t have a car.

I’d have no problem charging for parking, though note that since the garage doesn’t fill up, the marginal value of parking is currently $0. As ridership increases, charging for parking should become more viable. I’d also be pretty excited to see what someone could do in terms of adaptive reuse, and that might be a faster way to recoup the cost of building the garage. But until one of those things happens, why not make the best of things as they are today, and make it easy for drivers to turn left on Jefferson? I’d rather see people drive to a transit station than drive the whole way.

Principles for Freeway Improvements

Historically, freeway capacity improvements have often been made without putting too much thought into trying to get the most out of existing facilities. Problem: congestion. Solution: MOAR LANES. I think this is for the same reason you see streetcar projects popping up all over the place these days – other people’s money. For a long time, the federal government paid for 90% of freeway construction costs, so states didn’t really care how they spent the money. This has led to maintenance backlogs for states that built more than they could maintain, but that’s a separate problem.

Some readers are no doubt of the opinion that in the long run we should get rid of urban freeways. Let’s leave that debate aside for the moment and note that freeway removals are long-term projects and can be expensive, while the things I’m talking about here are short-term things we can do for cheap.

So, smarter freeway projects. Let’s assume you’ve already taken things like competing against transit and the arguments against new freeway capacity into consideration.  Here’s what you need to pay attention to when you design your project.

Make Things Better for Pedestrians and Bikes

At the end of freeway ramps, cars transition between an exclusive, high-speed facility and local streets, with lower speeds and competing uses. This means ramps are therefore prime locations for terrible incidents with drivers striking pedestrians and bikes. Therefore, it’s important for off-ramps to send a strong message to drivers: you’re not on the freeway anymore, and for on-ramps to send a similar message: you’re not on the freeway yet.

The best way to do this is with design features that force drivers to slow down or stop at the ramp terminus. A hard stop forces you to reset your expectations. To that end, here’s a quick assessment of how different types of interchanges perform:

  • Cloverleaf: probably the worst, since all turns to and from the freeway are free-flowing. Drivers coming off the freeway are likely to keep going too fast, while drivers entering the freeway are likely to accelerate into the ramp, increasing the chance of right-hooking a pedestrian or bicyclist. In addition, the ramp geometry results in long skewed crosswalks or the need to try to force pedestrians out of their way to a shorter crossing. If you try to cross a ramp like this with any regularity, you know how scary they can be.


Cloverleaf: the 710 at Willow. Note long & skewed crosswalks, large ROW needs, and weaving movements on freeway.

  • Partial cloverleaf: a little better, since it probably introduces a traffic light, but still has some free rights. A four-ramp partial cloverleaf is better than a six-ramp.


Six-ramp partial cloverleaf: the 91 at Lakewood. Less ROW and no weaving on the freeway, but still some free rights. In the SW quadrant, we have a crosswalk that forces pedestrians to take a circuitous path. In the SE quadrant, we have a skewed crosswalk.


Four-ramp partial cloverleaf: the 405 at Hawthorne. Note that the interchange ROW is tight to the freeway. The ramps intersect Hawthorne at a tight right angle, and this location has no right on red. This forces drivers to stop and reset.

  • Single-point urban interchange (SPUI) and diverging diamond: these interchanges were designed to move as much traffic as quickly as possible. Pedestrian and bike facilities are an afterthought, and to be blunt, they suck. SPUIs and diverging diamonds might be ok in a suburban or rural context, but they don’t belong in cities.


SPUI: the 10 at Archibald. The ROW is pretty tight, but the pedestrian crossings are skewed, and drivers are encouraged to speed by free rights.

  • Tight diamond: in this design, the ramps intersect the street in essentially the same configuration as a regular intersection. All traffic, including right turns, must stop before proceeding. This is the safest design for bicyclists and pedestrians, so when urban freeways are reconfigured, this is the design that should be used. Note that a properly designed partial cloverleaf can do this job just as well.


Tight diamond: the 405 at Culver. Minimal ROW impact, and the intersection of the ramps with Culver is like a normal intersection.

Reduce the ROW Impact of the Freeway

Freeways make gaps in the urban fabric. In newer areas of development that have grown up around freeways, it’s not that big of an issue, but in cities, freeways can be real barriers. Many older freeways were designed with a callous disregard for context, so any reconstruction projects should try to fix these problems.

Happily, there’s a lot of synergy between the goal of making things better for pedestrians and bicyclists and the goal of reducing the ROW impact. The interchange designs that minimize ROW impacts are also the ones that are best for pedestrians and bicyclists. If you’re in a dense urban area, there’s really no reason to ever build a loop ramp. The marginal benefit to traffic is just not worth it. The only exception to this is where the freeway crosses the intersecting road at a skew, like in the four-ramp partial cloverleaf shown above.

Make the Most of Existing Capacity

Adding lanes is the “dumb” solution, because it requires the least amount of thought. You don’t have to do any critical thinking about what’s causing the congestion. But adding lanes is also usually the costliest solution, and the most disruptive to the city, so adding lanes should be the improvement of last resort. That’s not to say it never makes sense. For example, where the 5 drops from five lanes to three lanes in La Mirada, it’s pretty clear that the inconsistent number of lanes is the source of congestion. (Note that theoretically, you could fix this by adding lanes in LA County or removing lanes in Orange County. If we want to do the latter, that’s fine, but we need to explain how we will accommodate the travel demand.)

However, in many cases, congestion is being caused by deficient design on the existing freeway. These issues should always be analyzed and addressed before adding lanes. The most common deficient design feature is inadequate weaving distance. This is a major source of congestion on many older urban freeways, which were built when the understanding of freeways was primitive, and have entrance and exit ramps placed too close together. Some examples of this in Los Angeles are the 10 between Western and the East LA interchange, the 110 between Florence and Adams, the 101 from the East LA interchange to the Hollywood Split, the 405 between Inglewood and the 110, and the horrible weaves on the 110 between the 10 and the Downtown exit, and between 3rd St and the Four-Level.

There are three options for addressing weaving problems caused by close interchange spacing:

  • Eliminate some of the on and off ramps to increase interchange spacing. This is the cheapest option, and it may be possible to recoup some costs by selling the old ROW.
  • Add auxiliary lanes or collector-distributor lanes. This is a moderate cost option aimed at easing, but not eliminating the weave.
  • Braid the ramps. This is an expensive solution requiring bridges, and probably ROW.

There are two key questions in choosing an option: how important is it to provide ramps to all these surface streets, and how much money do you want to spend? If you really need access to all the streets, auxiliary or C-D lanes will help. Braided ramps should be reserved for only the heaviest volume locations.

In general, I think removing ramps is underappreciated as a viable option. You help solve your freeway congestion problem. You save money. And you get to remove through traffic from neighborhood streets that probably shouldn’t have had ramps in the first place. If your interchanges are less than a mile apart, odds are you’re dumping freeway traffic into the wrong places anyway. Removing ramps is a way to improve neighborhoods. What’s not to like? We should be removing more ramps.

There’s also some synergy to be had with the previous two goals. Cloverleaf interchanges inherently have short weaving distances between the loops, so they can also cause congestion. They also take up a lot of ROW. They should be replaced with other interchange designs, preferably tight diamonds or, where the freeway is crossing at a skew, a tight partial cloverleaf. The 710 is littered with 1950s-era cloverleaf setups, so when that project goes forward, they should rebuilt in that manner. As a bonus, turning those interchanges into tight diamonds frees up some ROW that can be sold for commercial development or whatever.


In conclusion, freeway reconstruction projects on the older LA freeways should be looking to do the following:

  • Get rid of ramps where interchanges are too close together.
  • Get rid of loop ramps that waste urban space.
  • Square up ramp junctions and get rid of free right turns to make things safer for pedestrians and bicyclists.

We’ll see these principles in action in a new post soon.