Last week’s article discussed why we need to continue our program to slow down our streets to save lives, given the increasing traffic pressures on our existing streetscape (see https://smmirror.com/2023/08/s-m-a-r-t-column-the-30-mph-city-part-one/ ). This week, we will discuss the secondary but valuable benefits of a slower City.
Benefits galore:
- It’s quite simple: speed kills. A collision of a car with a pedestrian, bicycle, or motorcycle typically has the following likelihood of death depending on speed: 19mph=10%, 25mph=30%, 31mph=85%. So even if a City’s driving speed limit was actually 30 mph, a pedestrian’s chance of surviving a collision at that speed is still, unfortunately, very small. The slower our streets become, the safer our residents, workers, and visitors are.
- Lowering speeds reduces the probability of even having a collision by reducing typical braking distances: 19mph=44’, 25mph=81’, and 31mph= shocking 130’. Even if an unfortunate collision does occur, the shortened braking distance means the actual collision will be at a lower speed because, in all probability, some braking will have already hopefully occurred prior to the actual impact.
- Slower streets consume less fuel, thus reducing air pollution (read global warming). These reductions are available to electric and gas-powered cars, especially when the electric vehicles get their recharge from fossil fuel sources. Finally, slower speeds produce less particulate matter (brake shoe wear, tire wear, clutch wear, etc.). In the LA metropolitan area, excessive deaths (asthma, lung cancer, etc.) from the smog and particulate pollution of vehicles of all kinds exceed the death toll of collisions. The long-term health effects of combined smog and particulate matter shorten more lives per year than actual collisions.
- Slower streets are quieter streets. Our new Housing Element demands packing thousands of new residents in 7-10 story buildings along our major boulevards. Essentially, we are putting our newest residents on what will become our noisiest streets. It would be best for those residents to have quieter streets like those experienced on the side streets since excessive noise has well-known health impacts. People love active streets and places, but no one wants to live on a noisy street.
- Slower streets encourage people to feel safe walking and riding bicycles. Our relatively flat city, with relatively (so far) open streets and a mild climate, is perfect for year-round bicycling. But the vast majority of people do not use bikes, even for short trips, because they simply do not feel safe. When the actual travel time difference between cars and bicycles decreases via slower posted speeds, more people may be encouraged to take a bike. Likewise, our needed adoption of smaller and more efficient cars would be encouraged by slower streets. People do not feel safe in small cars at high speeds, so big cars predominate. But a slower City can speed the inevitable adoption of smaller cars because their statistical safety is maintained by slower speeds. Finally, more of these smaller cars can fit into a given parking area.
- Slower streets are better for the local economy. When drivers slow down, they can read business signs and become more aware of other pedestrians and street art. Finally, Covid showed us we can push open-air restaurants out into the street parking lanes, but the scariest thing, even with the protection of K rails, is when you are sitting just feet away from a bus or truck rushing by at 35 miles per hour. It’s always a better meal if the traffic is slower. People linger more at sidewalk cafes and storefronts when traffic is slower.
- Parents feel safer letting their kids walk/ride to school, knowing that the streets overall are slower and speed limits are strictly enforced. This is particularly true when young kids have to cross big boulevards alone.
- Slower streets will make self-driving cars (whose safety is still dubious) even safer since they are programmed to stay within the posted speed limit. This is particularly advantageous for self-driving vehicles, which struggle when trying to decipher and respond appropriately to ambiguous traffic situations.
- Law enforcement is easier on slower streets because speeding scofflaws stand out more.
- Traffic signal timing, to create a continuous green light driving experience, can be done equally well or better with slower overall traffic.
- Slower traffic can use slightly narrower lanes, enhancing the space available for bike paths, sidewalks, etc. This is useful when inserting valuable right and left turn lanes into existing roadway widths.
- Finally, slower streets reduce not only fatalities but also reduce serious traffic injuries, which typically exceed fatalities.
Do we really need to slow down our gridlocked City?
Of course, cynics will argue that we have already achieved this speed reduction through the perverse and worsening effects of gridlock. Unfortunately, this gridlock “safety” bonus, if real, only occurs, for now, during the nominal 4 hours a day, only five days a week of rush hour. The other 88% of the time, some of our streets are typically faster than they need to be for increased safety.
The discussion above seems car-centric, but it does not to imply that the unsafe behavior of bicycles, motorcycles, scooters, and pedestrians, which is increasingly flagrant, does not contribute to traffic fatalities. It’s just that cars are bigger and faster than those other transit modes, so they have an outsize effect on traffic deaths.
Will posting slower speed limits on just three streets work?
Clearly, it will not be enough alone in the overall traffic death count because it needs to be buttressed by all the other existing traffic safety efforts: traffic demand management, strict speed enforcement, driver and bicycle training, and drunk driving checkpoints etc., etc., to name just a few. Those are still essential, and they could be amped up by other technologies, such as car license readers that send the car owner a ticket when filmed at excessive speed or during illegal maneuvers. The public’s perception of speed cameras and their impact on safety can also influence their effectiveness. If people believe that speed cameras enhance road safety, they might be more likely to comply with speed limits. There will be public resistance to traffic cameras, which inevitably raise privacy/security issues, so lowering posted speed limits coupled with consistent enforcement is just the first step to possibly avoid the need for traffic cameras.
The only downside of slower streets is that it takes longer to get where you want to go. Fortunately, the time “penalty” for safer streets is remarkably small. For example, it takes about 8 minutes and 40 seconds to drive at current speeds (e.g., keeping up with existing traffic) the 2.8 miles along Pico from the east city border to Appian Way at noon on a typical Saturday. That’s an average speed of 19.5 mph. Doing the same drive, always staying under 30mph in this 35mph posted street, takes about 40 seconds longer or only a 7.5 % increase in travel time. The percent difference would be even smaller if the same test were done at rush hour since more time would be spent by each driver stopped in gridlock.
The City should continue to improve its nuanced program of traffic calming, particularly on the streets that are still over 30mph (e.g., Pico, East Ocean Park, Olympic, etc.). The safety of these currently 35mph streets will particularly benefit when reduced to 30mph during their upcoming multistory buildout. The idea is to make 30mph the default maximum speed for all urban drivers. Just their awareness of this limit will help our increasingly crowded City. The time penalties are very small, and the number of lives saved and serious injuries avoided makes this worth pursuing, not to mention all the other secondary benefits of slower streets.
By Mario Fonda-Bonardi AIA
S.M.a.r.t Santa Monica Architects for a Responsible Tomorrow
Thane Roberts, Architect; Robert H. Taylor AIA, Architect; Dan Jansenson, Architect & Building and Fire-Life Safety Commission; Samuel Tolkin Architect & Planning Commissioner, Mario Fonda-Bonardi AIA, Michael Jolly, AIR-CRE.
For previous articles, see www.santamonicaarch.wordpress.com/writing
