1) Greenview Drive
2) Montrose Traffic Circle.
Results:
- Narrowing the roadway on Greenview, by striping parking lanes, resulted in an 11% reduction in all speeders and a 21% reduction in motorists who exceeded the speed limit by 10+ mph.
- Constricting the westbound lane entering the Montrose traffic circle from 16 ft to 13 ft wide and adding splitter islands to the traffic circle reduced the number of speeders (25+mph) by 80%. Motorists traveling 30+ mph were reduced by 96%.
(click Greenview graph for larger figure)
(click Montrose graph for larger figure)
Posts
"Narrowing the roadway on Greenview, by striping parking lanes, resulted in an 11% reduction in all speeders and a 21% reduction in motorists who exceeded the speed limit by 10+ mph."
ReplyDeleteSo that means that 89% of the drivers continue to speed, and 78% of the drivers continue to speed 10+ over the limit.
This is unacceptable. This proves that "traffic calming" is ineffective.
Why not did a hole on each side of the street and insert STOP SIGNS, instead of wasting money from the city budget for traffic calming?
O.L.R.,
ReplyDeleteThank you for your thoughts.
The 11% reduction and the 21% reduction were a reduction in the number of speeders. It is therefore not correct to say that 78% of drivers continue to speed in excess of 10mph (that would truly be unacceptable). It means that 78% of people that were already speeding continue to speed. Based on the chart, that equates to about 8% of all drivers. While that is 8% too many, Greenview Drive is a very low-volume road. So, relatively speaking, it is better to have 8% speeding on Greenview than on Van Dusen Road, for example, where the number of daily cars is 17x that of Greenview Drive. Accordingly, Greenview Drive received a low-cost traffic calming treatment: $25 in paint to install parking lanes. That small amount reduced the number of speeds by 60 cars a day. It seems a fair return for a small investment.
Regarding your other comment regarding stop signs: Federal guidelines are in place for determining the proper traffic conditions that warrant a stop sign. These same guidelines indicate that stop signs are not to be used for traffic calming. Studies have shown that unwarranted stop signs actually make roads more dangerous. Drivers tend to speed up in between stop signs, so as to make-up for their perceived lost time. Also, when drivers are required to stop for traffic, but see no reason to, they develop contempt for them. This results in rolling stops and running of stop signs.
If there is a 11% decrease in "speeders" it still means that 89% of speeders still speed. Anything that cures something by less than 50% is a waste of time and money.
ReplyDeleteMincing my words doesn't make that 89% go slower.