We’ve all seen the graph: a person hit by a car going 40 miles per hour (mph) has an 85% chance of being killed. Reducing the speed to 30 mph cuts the odds of death in half; reducing speed to 20 mph drops the fatality rate by an astounding 94%. Even more dramatically, at 5 mph cars (and very cautious trucks), bikes, and pedestrians can all safely share the same street space. According to the US Department of Transportation, about 33% of vehicle-related deaths are speeding-related. Of those, around 40% occur in urban areas.
Almost every neighborhood feels that too many cars (and trucks) are driving through too fast making too much noise and endangering everyone. One impact is to severely limit the number of people who are willing to walk, bike, or even hang around outside with their neighbors. Especially affected: the elderly, the infirm, the very young, the slow moving. Especially impaired: public health, social connectivity, local businesses, and (because it is almost always worse in low-income communities) social equity.
The most effective way to slow traffic is through physical changes in the road and its surroundings. But despite progressive policy statements at the state and federal levels about the need to promote walking, bicycling, and transit as much as – or even more than – car traffic, current planning and operational procedures and practices continue to generally lead to car-centric results. Changing this requires elevating the concept of “desired” or “target” speed to a central place in all road transportation analyses and decisions, while broadening its interpretation to incorporate criteria relating to the promotion of non-car modes. As a step towards that goal, we also need to support two bills currently in the Massachusetts Legislature that would allow the local creation of additional 20 mph Safety Zones and reduce the Legislatively-set Statutory (default) speed limits on streets without Posted Limits.
After (or in fear of) an accident, or just to make their neighborhood’s public space more inviting for walking, bicycling, or simply being outside with others, the first impulse of many concerned citizens is to demand a traffic light – which unfortunately often ends up having little effect on car speeds before or after the intersection and may even cause some motorists to speed up in order to beat the light or make up for lost time. The second impulse is to demand that the local authorities find a way to reduce car speed.
Cars’ actual operating speed is affected by many factors. Some are specific to the individual motorist, car, or moment of time: personal attitudes and skills, vehicle capabilities, police presence, level of congestion, and the weather. However, because these vary widely across the population and times they don’t change the overall average operating speed.
Other factors are more external and permanent and affect almost every driver and car: the road’s physical structure, the signage and pavement markings, the surrounding environment, and the speed limit. Because they affect everyone in generally similar ways, these structural factors are considered the primary influence on overall operating speed. Of the physical factors, the infrastructural components — the physical and painted layout and signage – are mainly preset, based on the Design Speed chosen to guide planning when the road was constructed or upgraded.
But Design Speed is a conceptual tool, not a speed limit. Partly because straight wide roads invite it and partly because engineers understandably try to include a car-focused margin of safety to compensate for inevitable “driver errors” Federal Highway Administration researchers have shown that when roads are put into use their layout “often appear adequate for speeds far above the designated design speed.” Making matters worse, the higher manufacturing standards used for cars these days make going faster feel more comfortable, so motorists are likely to go even faster in a wider variety of road conditions. And we do go fast. Because the stress of our lives rushes us through the day, because our culture encourages us to push forward, and because it is so easy to press down on the gas pedal, most people (myself included) tend to drive as fast as the road comfortably allows.
In recognition of this reality, MassDOT’s Speed Zone Regulations state: “Numerous studies have indicated that drivers will not significantly alter what they consider to be a safe operating speed, regardless of the posted speed limit, unless there is constant heavy enforcement…[To be] both acceptable to the prudent driver and enforceable by police…the ideal speed limit is…[based on the] prevailing speeds of motorists on a particular section of a roadway under ideal conditions.”
Obviously, the best way to reduce car speed is to change road conditions. But, in the absence of a history of car accidents or a recent headlined tragedy, when local activists demand structural changes that would dampen traffic flow they are often rebuffed when the current legal speed limit (and local practice) allows higher speeds. And when they try to get around this by pushing for a Speed Zone Study to justify their desire for lower speed limits they run into the “prevailing speeds” issue – current transportation policy is implemented through formulas that speed limits can’t be lowered if as few as 15% of motorists are already going faster. And this is almost always the case: studies show that “the majority of speed limits are posted below the average speed of traffic.” Even worse: if a Speed Zone Study finds that the current threshold operating speed is high than the existing Speed Limit, the Transportation Agency is required to raise the speed limit — which is why most Speed Zone Studies get cancelled before their “official” end.
Catch 22 – it was exactly because local people felt that too many cars were going too fast that led to the desire to slow things down in the first place!
The source of the problem is the car-prioritizing values and procedures that remain at the core of transportation planning and analytic methods and expressed through current practices. According to Massachusetts’ Procedures for Speed Zoning on State and Municipal Roadways manual, “The goal of our Speed Limit Traffic Control Program has always been… in the best interest of the motoring public’s right to use a roadway in a reasonable and proper manner….” It is theoretically possible to stretch the words “reasonable and proper” to include all the other factors relating to the impact of motorized traffic on our social environment and public health as well as the rights of non-motorists to use public space. But, in procedural reality, the “motoring public’s right to use a roadway” to go as fast as “ideal conditions” allow takes priority. (For another procedural tool that leads to the same car-centric results, check out the way Level of Service analysis is usually done.)
In effect, the rules and procedures for setting speed limits are entirely focused on accommodating car drivers. Period. There is no method to incorporate any other factor besides simplifying enforcement. Safety of pedestrians? Encouragement of bicycling? Impact on the social environment in public spaces? No mention; no formal way to include; and certainly not prioritized.
The result is that despite widespread desire and many efforts to lower car speeds, it seldom occurs.
THE ROUTE FORWARD
There is a solution. It starts by affirming the core principal that motorist comfort should not be the primary determinant of Design Speed, road structure and markings, or the Speed Limit. This is not actually a new or off-the-chart idea. In fact, at both the federal and state levels, official policy now insists that the safety, comfort, and mobility of people traveling by foot, bike, bus, trolley, and train be given equal consideration as those in cars. Former US Transportation Secretary LaHood issued a new multi-modal-favoring policy and blogged that “This is the end of favoring motorized transportation at the expense of nonmotorized.” In Massachusetts, because of its aggressive “mode shift” goals to triple the number of walking, bicycling, and transit trips, official policy even can be interpreted as prioritizing the needs of non-car users – an interpretation reinforced by the recent Healthy Transportation Policy Directive.
However, there remains a huge gap between policy and practice. One way to begin operationalizing these policies is to put the concept of Target Speed – the “desired operating speed” – at the core of not only the Design Speed selection and Speed Zone Study processes but also every routine restriping, maintenance, and repair job. This relatively new piece of Transportation jargon needs to be understood, and if necessary redefined, to include everyone’s safety; and the criteria used to calculate it must include the impact of car (and truck) movement on people’s willingness to use other modes, as well as on the large influence of transportation on the quality of life in the surrounding neighborhood. And we need to go beyond statements of policy and principle to have the new approach incorporated in the guidelines, formulas, and evaluations of every Traffic project.
While MassDOT adjusts its internal operations, the process can be moved forward through passage of several bills now under Legislative consideration. H.550, sponsored by State Representative Denise Provost, will authorize locally-designated 20 mph Senior Citizen Safety Zones in addition to the current School Zones – a first step towards allowing the creation, at local discretion, of Safety Zones near hospitals, playgrounds, railroad stations, senior housing, even business areas. H.3129, also sponsored by Representative Provost, will set 25 mph, instead of the current 30, as the default speed limit for local roads in urban districts without explicit Speed Limit posting. Call your Representative and let them know what you think!
…THE REST OF THIS POST IS A DETAILED EXPANSION OF THE ABOVE MATERIAL…
Thanks to Tom DiPaolo and Peter Furth for extensive feedback on previous drafts; the remaining errors are entirely my own responsibility.
Related previous blog posts:
_____________________ Continue reading