Rounded Curbs and Limit Lines

Back in the day when I was pursuing my Masters in Urban and Regional Planning, one of the first lessons we learned was that America is the “car country.” While this reality vexed academics and public transportation aficionados, it was quite popular at the voting booth. We also learned that the Defense Highway Act of 1956 had little to do with defense, and the Home Loan Mortgage Insurance Act of the same period had little to do with homes. Instead, both had a lot to do with cars. 

Before these regulations took hold, our non-farm population was largely concentrated in enclaves that could be served productively with public transportation. After these regulations were promulgated, this was more and more difficult to do. Without federal subsidies, the last transit system holdout that provided more than a skeleton of cherry-picked routes was New Jersey Transit. But even this holdout pretty much shut down in 1969. 

These systems were rescued in 1964, when President Johnson created the Urban Mass Transportation Administration (now the Federal Transit Administration) as an element of the Model Cities Program, housed in the Department of Housing and Urban Development (HUD). The public transportation community hardly controlled the roadways, even with 80 percent of the buses paid for by taxpayer dollars (now from the FTA). Nor did they remotely control their design and configuration. Resembling states whose borders often formed right angles, our street network consisted largely of straight lines and sharp corners at right angles. Even today, in many communities, the fact that millions of commercial vehicles with large wheelbases must traverse these streets barely enters the mindset of traffic or highway engineers. 

The Limits of Coordination 

Rounded Curbs and Limit Lines 1Certain modes of public transportation enjoy limited coordination. In the school bus community, stops in many states require approval by local or state law enforcement officials. Even here, only a single criterion is generally employed: the need for a minimum straight sightline distance in both directions from the stop – typically 300 feet. 

Transit agencies become a bit more involved in stop coordination and approval with fellow agencies, and stops on local roads are typically approved (or blessed) by both law enforcement officials and highway engineers. State DOT officials and highway patrols are typically involved when the stops occur on state highways. Particularly in the case of transit, criteria for stop selection, design and treatment can be elaborate. 

The principal “bible” containing recommendations and illustrations is Report #19: Guidelines for the Design and Selection of Bus Stops by the Transportation Research Board’s Transportation Cooperative Research Program. Beyond citing some rigorous tradeoffs for various stop positions, the TCRP Report devotes considerable verbiage and diagrams for stop design and treatment, including scores of unusual configurations, many of which remain innovative even today. 

Rounded Curbs and Limit Lines 2What the TCRP Report does not cover – and which very few documents do – is how to render parts of the roadway (other than stops) conducive to safe bus usage. The two most salient examples of this tendency are thoughtless positioning of limit lines and the rarity of rounded corners. Every bus and motorcoach driver has been frustrated by an almost universal failure to factor in the spatial needs for the movement of buses and motorcoaches into the design of intersections and the placement of limit lines in front of them, with only some communities providing exceptions. 

These problems were centerpieces of two recent, previous articles in NATIONAL BUS TRADER: “The Danger Deterrent” (April, 2016) about left turns, and “Dancing in the Oncoming Lane” (August, 2016) about right turns. While both articles focused on the risks of striking pedestrians and parked cars during turns, they did not dwell on the solutions. This article does. 

Rounded Curbs and Limit Lines 3Even a bus-driver trainee struggles with the task of turning right into a single perpendicular lane. In most cases, drivers face a dilemma. To make a proper “square” turn (i.e., aligning the rear drive axle with the near-side extended curb line of the intersection), the driver must push the vehicle’s nose deeply beyond the perpendicular right lane, then swing the bus sharply to the right (see “The Steel Wave” in the January, 2013 issue of NATIONAL BUS TRADER). They often spend considerable time in the perpendicular right line – often one with a limit line far too close to the corner. In some streets, the length of the bus or coach makes such a turn impossible. The nose of the bus would crash into a building on the far side corner. 

To avoid this, the bus or coach must necessarily begin the turn considerably before its rear axle aligns properly with the extended near-side curb line. Since the rear tires pursue a diagonal, this means that the rear tires must often roll over the sidewalk on the corner. In many cases, the rear of the bus sideswipes parked vehicles (or others waiting at a transit signal – often at or illegally-parked in front of a limit line much further placed much too far forward than the bus or coach needs it to be). 

Rounded Curbs and Limit Lines 4Sometimes, buses and trucks simply get “stuck” – requiring drivers to summon dispatchers who then must summon law enforcement offers to help rescue them. Since 1997, I myself have rescued hundred of such buses (and trucks) in such a jam in Manhattan. Serving as an unofficial traffic-control Samaritan, I have directed fellow motorists to back up (when behind buses or coaches) or otherwise move out of the way. I have helped the bus or coach driver back up, either helping direct it around the corner (often by serving as a human limit line on the perpendicular street), or informing the drivers about alternative streets to navigate to their destinations, where the challenges of the corners and limit lines were less. 

To squeeze these leviathans around these intersections too small or narrow to accommodate them, the driver must “cheat” – either rolling the nose over the far-side corner sideway or rolling their rear tires over the near-side corner sidewalks. Sadly, these compromises are often required for left turns. 

As noted, even buses and coaches turning left have similar problems – and as noted in “The Danger Deterrent,” the speed at which bus and coach drivers often translate these results in a lot of “oops” situations. “Oops, there is no way I can avoid mowing down that pedestrian in the crosswalk.” “Oops, there goes the left-front corner of the motorist’s vehicle waiting at the limit line.” Some of the same constraints that make right turns difficult make left turns difficult, although to a lesser degree. Beyond the illusion of speed at which bus and coach drivers think they can make a left turn, the most common are: 

• intersections too narrow for buses or coaches to make a proper “square” turn into (i.e., the distance from the front cap to the drive axle is longer than the width of the entire roadway)

• the size of the bus or coach is too long for the intersection. 

Rounded Curbs and Limit Lines 5If he or she chooses to turn, the driver faced with this situation has no choice but to “cheat.” This most commonly takes the form of the driver turning with the drive axle far behind the extended near-side curb line. The problem with this approach is that the bus or coach must turn so sharply that it can obliterate the right-front corner of a vehicle parked in the oncoming lane of the perpendicular street. 

The problem is that transit schedules are often obscenely too tight, a factor that contributes to so many turning accidents. Racing around corners improperly becomes habitual in drivers’ efforts to comply with their schedules. Some system’s drivers actually swoop into crosswalks occupied by pedestrians – in the hope that they can turn behind them. Of course, this problem works out far less well when the pedestrian is crossing in the same oncoming direction as the bus or coach, rather than in the same direction as the bus or truck was traveling before the turn.

Between a Rock and a Boulder

There are quite a few reasons where drivers are forced to make one unsafe tradeoff versus another – particularly when the schedules are tight:

• The limit lines of perpendicular streets have been placed too far forward, not leaving the turning bus or coach enough room to “dance in the oncoming lane.”

• Innovative traffic signalization configurations (like extended amber cycles) are not employed.

• Rounded corners, which would greatly eliminate the amount of time right-turning buses or coaches would have to inhabit in the oncoming perpendicular lane, are not available.

• “Leading green” pedestrian crossing signals would ease the situation by giving pedestrians time to cross intersections before other vehicles (obviously including buses and coaches) do.

• Traffic “cops” – who could mitigate many of these problems and contribute to their solutions – have become as rare as live bureaucrats or corporate receptionists answers telephone calls.

Tactics and Strategies

Frankly, there is little that can be done about these things at the tactical level. Even less can be done strategically. As a nation unable to repair and maintain 70,000 bridges, tunnels, rail-road beds, highways and byways, funding the enormous volume of even relatively low-cost solutions to these deficiencies would be daunting. At the same time, many of the solutions to the problems noted cost a pittance. All that is needed is a 10-foot-wide stripe of white paint (and 10 feet of black to cover over the improperly placed former white lines). Tweaking the sequence of lights and pedestrian crossing signals is almost trivial. Rounding corners is a bit more expensive. All these solutions pale at the cost of adding traffic signal systems, or even modifying existing signalization. However, it is important to note again that the vast majority of these improvements lie at the low-cost end of the spectrum.

Advancing the Public Safety Agenda

 Fully Ergonomic Driver's CompartmentAs noted, motorcoach entities do not have the clout (much less the regulatory authority) to modify intersections. Yet our school bus and, particularly, transit industry colleagues do. Other than the special problems that 45-foot motorcoaches pose, transit agencies and their contractors (many of which are motorcoach companies) encounter these very same problems. So why is little or nothing done?

In an innocent (or perhaps naive) way, I wonder why our industry cannot strengthen the alliance with our transit and school bus cousins (after all, we share the same unions, and experience the same types of accidents), and make a push for more bus- and coach-friendly roadway design. There are critical changes that can be made with just a simple knowledge of a bus or coach’s wheelbase, turning radius and small can of white paint. At the planning level, would it really be so hard to not influence a planning/programming agency’s future plans to round off a few corners, at least in residential areas? (Problems with buildings close to them, and the access around the rounded corner notwithstanding.) I also do not think a campaign to address those intersections most challenging and/or with the highest rate of turning accidents would exactly “break the bank,” much less encounter political resistance. 

Change without the Bandwagon

Rounded curbs and limit lines number 7It is far too late to turn America into Europe. Our urban form is what it is. Our starved public transportation services are no match for our car-crazy society and its car-friendly voting agenda. This is even more true lately with the decline in gasoline prices.

There is regrettably no bandwagon to jump on for public transportation advocates, and no shortage of insipid ideas (e.g., the proposal for a $48.5 billion nationwide passenger rail system) to knock off the bandwagon’s wheels. In contrast, measures to make public transportation safer, more efficient and more attractive – like limiting shift inversion in driver assignment of testing all commercial drivers for Obstructive Sleep Apnea – drive “choice riders” further away from public transportation, tipping the equation away from our industry. Even so, it is really too much to ask that we begin to model our auto-friendly environment more intelligently to keep even the beneficiaries of these changes – our motorists and pedestrians – safer? As our bus schedules grow tighter and tighter, our training poorer and our monitoring nonexistent, is it too much to ask that our public transportation community argues for safer infrastructure along the way?

Perhaps we must resign ourselves to the impossibility of effecting even low-cost improvements in this infrastructure. The relentless substitution of robots for personnel does not bode well for addressing changes that robots cannot make or evaluate. Once again, the public transportation community finds itself victimized by failures, incompetence and indifference that lie beyond our control. This is hardly consistent with the hackneyed onceevery- four-year-dirge of “Making America Better.” If we cannot repaint a limit line 30 feet further back on a side street, or match a bus’s or coach’s length to the width of a street into which it must turn, we are delusional in the belief that our roads, tunnels and bridges are going to improve. Sadly, we are going backwards in public transportation safety – and most disturbingly, in new ways. 

Publications: National Bus Trader.