Wednesday, August 1, 2007

Daniel Street Stop Sign

Barry Bergman has a letter in today's TAB (fourth of five letters on the page) responding to my Stop Sign op-ed from last week. Mr. Bergman applies my op-ed to the situation at Jackson and Daniel Streets and raises an interesting question about the relative safety of a stop sign and a curb at the bottom of the hill.

First though, I think I may have been unclear. Mr. Bergman attributed to me the position that "roadway redesign is always preferable to stop signs." In fact, I believe that stop signs are appropriate where the right of way is unclear. The point I intended to make was that roadway redesign is the better solution when there is no right-of-way issue and the intention is to slow traffic.

That leaves two issues from Mr. Bergman's letter:

  • What's the point of the Daniel/Jackson Street intersectionredesign?

  • What's the better solution for Daniel the intersection

Mr. Bergman writes:

For example, at the intersection of Jackson and Daniel streets, Jackson Street veers off at a 90-degree angle. In order to clearly establish that Jackson Street has the right of way, the city of Newton is proposing a bump-out in the westbound lane of Jackson Street at this intersection to encourage traffic to continue southbound on Jackson Street to Route 9 rather than continuing west to Parker Street.

But, clarifying the right of way is not the point of the Daniel/Jackson intersection redesign. The point is to slow traffic heading westbound on Jackson to Daniel.

The intersection doesn't have a right-of-way question. The vast majority of traffic through this intersection travels eastbound from Daniel to Jackson or westbound from Daniel to Jackson. Eastbound traffic from Daniel has a stop sign. They clearly do not have the right-of-way. No clarification necessary.

Westbound traffic only has a potential conflict with traffic from the south turning left from Jackson to Daniel. Since there is virtually no traffic making that turn, there is no conflict. The best evidence that there is no conflict? Westbound traffic speeds dangerously through the intersection, hence the effort to calm the traffic.

The intention of the bumpout is to cause westbound traffic to slow before entering Daniel Street. In fact, it is explicitly a design goal not to encourage traffic to continue down Jackson or to use Walter as an alternative to Daniel. (Whether that design goal will be met is the reason for another round of trials once school starts.)

Had resolving the right-of-way been the issue, stop signs might have been appropriate. The reason that stop signs were rejected by Traffic Council at the intersection (two or three times, depending on how you count) is that there is no need to clarify the right-of-way. The need is to slow traffic.

Now what's the safer way to slow traffic at Daniel and Jackson? Mr. Bergman suggests that a stop sign at the bottom of a hill is a safer way to slow motorists than introducing a curb and a turn at the bottom of the hill.

A bump-out on Jackson Street at the bottom of a long hill would be a hazard in the winter. It is easy to see how a westbound motorist could collide with it or cause an accident when trying to avoid it. Stop signs at this intersection are a safer method of controlling traffic flow than road redesign

As I wrote in my op-ed, the problem with stop signs where they are not needed to clarify right-of-way is that they become routinely ignored. This is a problem that is weather and conditions independent. Even if Mr. Bergman is right that there is a problem in bad conditions, it would have to be weighed against the year-round problem of non-compliance.

But, I don't think that a redesign is any worse than a stop sign in bad conditions, or when a motorist is unfamiliar. (By the way, most of the traffic on Daniel and Jackson is local residents, traffic to and from Bowen School, or cut-through. Lack of familiarity is not really an issue.) For starters, a turn requires the motorist to slow less than a full stop would. If it's slippery, how is it safer to require more of the motorist?

Reading between the lines, it appears Mr. Bergman is suggesting that a stop sign provides a greater margin of error. An out-of-control driver only blows through a stop sign, which, using Mr. Bergman's logic, is better than having him hit a curb.

I think that gets to the heart of the matter. To me, it's the concern for the potential damage to a car that is going to make a curb redesign much more effective in getting the driver's attention and promoting slower and safer driving.

Motorists will use the margin of error that Mr. Bergman would provide to drive faster. Without that margin of error, with the concern about running over a curb, drivers will provide their own margin of error. There is nothing like an appeal to a driver's sense of self-preservation to change driving behavior.

To be clear, the point isn't to make it unsafe to drive through the intersection. The point is to make it unsafe or uncomfortable to drive fast through the intersection. If it is unsafe or uncomfortable to drive fast, drivers slow down, making it safer for all of us.

A gentler way to put this: a large, ambiguous intersection encourages speeding. A narrower, better defined intersection promotes more caution on the part of the driver.

Finally, Mr. Bergman's letter overstates the case. Newton is filled with turns at the bottom of hills. When it snows, we rely on the City to make these roads dry enough to make the turns slowly. From the DPW's own pages:

In general, it is the goal of the Department to have all streets fully cleared within eight hours after an average storm has ceased.

Jackson is a school route. It gets attention pretty quickly.

More importantly, we rely on motorists to use good judgment when driving down these hills. If the Jackson Street hill is snowy or icy, it's up to drivers to go at a speed where they can not only slow to make a turn, but come to a complete stop in the event of an emergency.


Barry Bergman said...

As the city of Newton has no intention of putting additional stop signs at the corner of Daniel and Jackson, I think this is a dead issue. A much bigger issue is the placement of the propose bumpout at the Daniel/Jackson street intersection. The placement of this bumpout diverts westbound traffic away from Daniel Street to continue southbound on Jackson. If the purpose of this bumpout is to slow traffic it should be placed east of the intersection.

Adam said...

The intersection is question has ambiguous width and needs to be narrowed. No intersection today would be designed in this manner. The contour of Jackson Street dates back far back before the invention of the automobile; the addition of Daniel Street back when Newton was still a trolley suburb and before individuals sped around in SUVs to work and to bring their kids to school (and there was no Bowen School until the 40's, I believe). Rethinking this intersection has many benefits. Traffic engineers assured us in a study that Jackson-Daniel will still be the primary route and continue to account for the vast majority of traffic. Jackson and Walter Street already have the benefit of sharp turns; Daniel's will be slight and there will be only one, making much less resistance.