Tag Archive for 'road diet'

Road Diet Data: Studies show projects lead to safer roadways

The Seattle Department of Transportation has been performing road diets or road rechannelizations for decades and argues that these projects bring about safer streets without affecting traffic volumes. SDOT collects data on traffic volume, vehicle speeds, and collisions both before and after each project. In a joint effort with Seattle Neighborhood Greenways, I’ve reviewed the studies and found SDOT’s claims to be true as you can see in the key data presented below.

Looking at the numbers, there is some change in roadway volume after the projects, but no consistent pattern that would suggest roadway capacity is being unduly limited. On the positive side, there are significant reductions in aggressive speeding (drivers going 10 miles per hour above the speed limit), including a 93% decrease from the Nickerson St road rechannelization. All collisions are down as a result of these projects and injury collisions have been decreased even further, ranging from a 17% to a 75% decrease.

In short, road diets are a powerful tool the city has to work towards the newly-announced Vision Zero plan.

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Walking news roundup

There’s a lot of news out there to cover – here are a few stories:

And a couple SDOT news releases that I don’t have links for:

  • “Seattle Department of Transportation’s Roadway Structures crew will construct a new staircase near the southeastern city limits at 72nd Avenue South between Rainier Avenue South and South Taft Street.” The stairway will be closed starting next Monday through early May. “The new staircase will be wider with hand rails on both sides, and will sport a new bike runnel making it easy to roll a bike up and down the stairs.”
  • “Repairs are underway on the Duwamish Trail in West Seattle. The asphalt trail has been heavily damaged in places by tree roots and needs to be repaired for bicyclist and pedestrian safety.”
  • NE Ravenna Blvd between Green Lake and 15th Ave NE will be repaved. “Work includes grinding and removing the existing asphalt roadway, repairing areas of the concrete roadway base, repaving, upgrading pedestrian curb ramps and building a curb bulb at E. Green Lake Drive N. and N.E. 71st Street. Work is expected to be completed by the end of summer, dependant on weather conditions.”
  • Also, the pedestrian paradise known as the Ballard bridge will have a closed west sidewalk starting next Monday and continuing into April due to a painting project.

One final thing – the nomination period for the worst intersection in Seattle ends this Sunday.

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Road diet on Nickerson found to improve safety, will other streets get a road diet?

SDOT has released a report on the Nickerson St road diet and found that by reducing the number of lanes for cars, safety has improved. Collisions, overall vehicle speeds, and the number of speeders have been reduced with minimal impact to traffic volumes. The Mayor outlines the good news:

Completed by the City in August 2010, the modifications have produced the following results:

  • Reduced collisions by 23 percent over a one-year period (compared to the previous five-year average)
  • Motorists traveling over the speed limit have declined by more than 60 percent
  • Top-end speeders (people traveling 10 or more miles over the speed limit) have fallen by 90 percent
  • The 85th percentile speed dropped from 40 mph and 44 mph westbound and eastbound to 33 mph and 33 Westbound and Eastbound. This is an 18 and a 24% reduction in speed.
  • Traffic volumes remain roughly the same with no evidence of traffic diversion.

This is the 27th successful road diet implemented by SDOT since 1974. And, with yet another roadway safety measure in place, the question must be asked: why isn’t SDOT implementing more of these safety measures?

We recently pointed out that 28 pedestrians have died in locations that may be eligible for a road diet. Since then, we’ve profiled three streets that may be ideal candidates for SDOT to consider next: 35th Ave SW in West Seattle, 23rd Ave in the Central District / Judkins Park, and S Jackson St in the International District. Let’s compare these three streets with Nickerson St to see whether these other streets may deserve the same successful safety treatment as Nickerson and 26 other Seattle streets.

First, we’ll start by looking at traffic volumes. SDOT looks at the total number of cars that use a roadway before implementing a road diet. Streets with average daily traffic counts above 25,000 are not good candidates, and presumably lower volumes make for better candidates, though road diets have minimal impact on overall volume. Using SDOT’s 2010 traffic volumes, here are the four streets compared, from lowest volume to highest:

  1. Jackson St: ranges from 10,200-13,600
  2. 23rd Ave: 13,400
  3. 35th Ave SW: ranges from 16,100-22,700
  4. Nickerson St: 22,300

Let’s look at another metric. While Walk Score is not an official criteria used by SDOT, it indicates the walkability of a location and is correlated with the number of pedestrians in an area. Streets with more pedestrians may be more deserving of measures that make the pedestrian environment safer and more pleasant. We took a sample Walk Score of 2-3 locations along each of these streets and are ranking them from highest (most walkable) to lowest (least walkable).

  1. Jackson St: 90
  2. 23rd Ave: 86
  3. Nickerson St: 81
  4. 35th Ave SW: 75

While the last two comparisons were interesting, the primary purpose of a lane rechannelization is to improve safety and the most dangerous streets should be looked at the hardest. We looked at this map of nationwide road fatalities, and counted the deaths that have occurred on each of these roadways from 2001-2009 to rank them in terms of urgency for safety improvements:

  1. 35th Ave SW: 4 roadway fatalities (including 2 dead peds)
  2. 23rd Ave: 4 roadway fatalities (2 dead peds)
  3. Jackson St: 3 roadway fatalities (3 dead peds)
  4. Nickerson St: 1 roadway fatality (0 dead peds)

Of our comparison group, Nickerson St has been the safest, is the second least walkable, and has the highest traffic volume. Still, a road diet was implemented and now has been shown to be a success. If a road diet can work there, then surely it can work on these other streets. How many more people will have to die before SDOT implements road diets on 35th Ave SW, 23rd Ave, Jackson St, and other locations where people are killed on Seattle’s roads?

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Deadly Seattle Street: S Jackson St in the ID

Walking in Seattle is profiling some of Seattle’s deadly roadways that could be candidates for a lane rechannelization, or road diet.

A road diet involves restriping the roadway, often to add a center turn lane and bike lanes. The effect is that vehicles slow down and the roadway is safer for all users. SDOT considers a roadway a good candidate for a road diet if people often speed on the roadway, if there is a history of collisions, and if a road diet wouldn’t significantly impact traffic volumes.

Jackson St at 5th Ave

Jackson St at 5th Ave

Walking in Seattle nominates Jackson St in the International District as a good candidate for a road diet.

From 2001 to 2009 there have been three pedestrian fatalities along Jackson. At 5th and Jackson a 74-year-old woman was killed at 11:30 on a Friday in February. Later that year, an 81-year-old man was killed at Jackson & 10th on a Wednesday morning in June. In 2002, a 69-year-old woman was killed as well.

The roadway currently has four lanes of traffic, with parking lanes on each side, yet only carries 10,200-13,600 vehicles daily, far below SDOT’s maximum limit of 25,000 vehicles for implementing a road diet. While a road diet may not have prevented these fatalities, road diets have been proven to improve safety. Automobile speeds are lower and less variable, and bicycle lanes help make the roads safer for more users. By lowering vehicle speeds, pedestrians are safer as well – a pedestrian struck by a vehicle traveling at 40mph is 85% likely to die, however if the vehicle is only going 30 mph, the pedestrian has a 50-60% chance of survival.

Jackson St, like 23rd Ave and 35th Ave SW, is a street that should be made safer and should be considered for a road diet.

Should SDOT implement a road diet on S Jackson St?

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Deadly Seattle Street: 23rd Ave

23rd Ave

23rd Ave, another good road diet candidate

Walking in Seattle is looking at deadly streets that may be good road diet candidates. The list included 28 different locations – just a fraction of the 90 locations throughout the city where a pedestrian had been killed between 2001 and 2009.

With four people having been killed in less than one mile of roadway between Yesler St and I-90, Walking in Seattle nominates 23rd Ave as a good road diet candidate. A road diet on 23rd Ave would improve road safety by re-striping the roadway to add a center turn lane and bike lanes, thus slowing vehicle traffic. Pedestrians are much more likely to be killed by a car traveling at 40 mph than by a car traveling at 30 mph.

At 10 pm on January 4, 2008, a 53-year-old female pedestrian was killed at 23rd & Lane in the Judkins Park neighborhood. On May 21, 2009, a 74-year-old man was struck and killed at 23rd & Main at 3 in the afternoon. In 2004, a 57-year-old motorcyclist died at 23rd and S Judkins St. Two years later, in 2006, a 26-year-old police officer was killed at 23rd and Yesler, when a speeding car ran a light.

This particularly deadly section of 23rd has four lanes of vehicle travel, with no sharrows or bicycle lanes and few marked crosswalks. There is also a curve and an incline that limit visibility. The daily traffic volume here is only 13,400 vehicles per day, well below SDOT’s maximum threshold of 25,000 for implementing a lane rechannelization. With the low visibility, low traffic volume, and high number of fatalities, this section of roadway would be an ideal candidate for a road diet that could prevent further death of all roadway users.

Should SDOT implement a road diet on 23rd Ave?

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Deadly Seattle Street: 35th Ave SW in West Seattle

35th Ave SW, a good road diet candidate

One of Seattle’s deadly streets that deserves more attention is 35th Ave SW in West Seattle. This street appeared twice in our list of locations of fatal pedestrian collisions that deserve further study. Walking in Seattle nominates this street for special consideration by SDOT as a road diet candidate.

A lane rechannelization, or road diet, involves re-striping the roadway, and in the case of 35th Ave, would add a center turn lane and bike lanes, and have one lane in each direction for motor vehicle traffic. The effect is that traffic flows more smoothly, thanks to the center turn lane, drivers go more slowly, and all users are able to use the roadway more safely.

The road carries 4 lanes of vehicle traffic in addition to a lane of parking on each side of the street. This makes the road width around 54 feet, which takes someone walking a normal speed more than 13 seconds to cross – a long time to be in the middle of a deadly roadway. In one area, marked crosswalks are half a mile apart.

An 85-year-old man was struck and killed on this street in 2007 at SW Othello St. A 39-year-old man was also killed on this street when he chased after his dog. This incident was covered by West Seattle Blog when it happened. While the speed of the vehicle who hit him isn’t available, road diets do reduce vehicle speeds. A pedestrian hit at 40 mph is about 85 percent likely to die; a pedestrian hit at 30 mph is about 40 percent likely to die.

Between 2001 and 2009 there were also two non-pedestrian fatalities on the roadway as a 27-year-old female cyclist was struck and killed at SW Graham St in 2006 and a 77-year-old driver was killed in a collision at SW Thistle St.

According to SDOT’s traffic volume data, the daily traffic volume on this road ranges from 16,100 to 22,700 vehicles per day. SDOT’s maximum threshold for implementing a road diet is 25,000 vehicles per day.

Right now the road has no bike lanes or sharrows and limited crosswalks. While it’s not certain that a road diet would have prevented these needless deaths, safety improvements are needed and could be provided by a road diet.

What do you think?

Should SDOT implement a road diet on 35th Ave SW?

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Could road diets have saved the lives of 28 pedestrians?

Walking in Seattle analyzed pedestrian fatality data* from 2001 to 2009 and found that 28 of Seattle’s 90 fatal pedestrian collisions occurred on roads that may be eligible for a lane rechannelization.

A lane rechannelization, or road diet, involves re-striping the roadway, often to add bike lanes or reduce the number of lanes for motor vehicles, with the intent of improving safety by slowing vehicle speeds and shortening crosswalk distances.

Through usually controversial when proposed, 26 road diets have been successfully implemented in Seattle since the 1970s. Streets that have recently been rechannelized include Stone Way, Fauntleroy Way, Nickerson Street, and 125th Avenue. According to pro-pedestrian organization Feet First, “When [road diets are] done properly at appropriate locations, all users benefit.”

One benefit of a lane rechannelization is lowered speed. The road diet on Nickerson Street has dropped motor vehicle speeds from 40-44 mph to 34-37 mph. A pedestrian hit at 40 mph is about 85% likely to die; a pedestrian hit at 30 mph is about 40% likely to die.

Since the road diet on Stone Way, Seattle’s Department of Transportation reports that collisions on that street have dropped by 14%, injury collisions have dropped by 33%, and collisions with pedestrians have dropped a full 80%!

SDOT doesn’t have a specific road diet program, but “we have been using rechannelizations as part of our paving program or proactively as part of other work,” says spokesperson Rick Sheridan. A road diet is a relatively inexpensive and reversible way to compensate for shortcomings of the roadway design and “one tool to improve safety through traffic calming.”

SDOT considers a roadway eligible for a road diet if vehicles routinely exceed the speed limit, if there are a history of collisions on the roadway, and if the lanes can be reduced without significantly impacting the current travel volume. SDOT considers 25,000 vehicles per day as a maximum volume for a four-lane roadway to receive a lane rechannelization.

Walking in Seattle has applied the above criteria to the 104 pedestrian fatalities (a result of 90 collisions) that have occured from 2001-2009 to come up with a list of roads that could be eligible for changes to the roadway striping. We feel that 28 of these collision sites deserve further study by SDOT:

Date of Collision Street Name Neighborhood 2010 Traffic Volume** Walkscore at Fatal Collision
9/12/2001 5th Ave Downtown 10800 100
9/23/2001 SW Alaska West Seattle N/A 86
6/7/2002 S Jackson St International District 13600 83
7/31/2002 35th Ave NE Wedgwood 15400 69
11/2/2002 35th Ave NE Wedgwood 15400 77
1/5/2003 S Jackson St International District 13600 86
6/16/2003 5th Ave Belltown 10800 98
7/3/2003 NE 130th St Haller Lake 19900 37
12/21/2003 Rainier Ave S Rainier Beach 18000 68
10/1/2004 15th Ave NE University District 8900 97
1/5/2005 Swift Way Beacon Hill 7400 71
11/10/2005 E Cherry St Central District 8300 86
12/14/2005 Alaskan Way Downtown 12600 82
2/8/2006 Rainier Ave S Brighton 23900 51
11/2/2006 4th Ave Downtown 18600 98
11/14/2006 SW Admiral Wy Admiral N/A 80
4/21/2007 24th Ave E Montlake 20000 62
10/27/2007 35th Ave SW High Point 20200 65
11/20/2007 16th Ave SW 98146 5100 71
12/19/2007 Pinehurst Wy NE Northgate 10900 86
1/4/2008 23rd Ave S Atlantic 13400 85
3/30/2008 1st Ave S Pioneer Square 24700 83
6/25/2008 Des Moines Memorial 98108 N/A 52
8/10/2008 35th Ave SW North Delridge 22700 48
8/23/2008 E Madison St First Hill 21900 98
9/22/2008 California Ave SW West Seattle 12600 85
6/17/2009 S Jackson St International District 13600 83
11/11/2009 NE 50th St University District 21800 98

Click for a map of locations

23rd Ave S

23rd Ave S, a potential road diet candidate

Many of these roads have four lanes of vehicle traffic and could have a center turn lane added, similar to other road diets. Some of these locations only have two lanes of traffic, like California Ave and Adrmiral Way, however the current lanes are wide and encourage higher speeds. By adding bike lanes and striping the parking lane, the main road space would be constrained and drivers would slow down.

While the city has been falsely accused of waging a “war on cars” through implementation of road diets, these statistics suggest that the city’s efforts have not been aggressive enough at reducing roadway fatalities.

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Mayor approves 125th St rechannelization

We’re a few days late to report this, but the mayor has authorized SDOT to move forward with the road diet on 125th St.

The project was originally proposed by SDOT last August, and faced some initial opposition. As a result, SDOT spent additional time reviewing public input and doing further analysis, resulting in a reaffirmation of SDOT’s proposal to change the roadway. SDOT’s recommendation to the mayor re-energized opposition, however the mayor has approved SDOT’s proposal, and the road diet will happen.

The mayor sent a lengthy response to people who had contacted him on the issue, explaining his rationale on the decision. Seattle Bike Blog has reproduced the mayor’s letter in its entirety.

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Petition to support NE 125th Road Diet

In response to opposition to changes that SDOT has recommended to 125th St NE, Cascade Bicycle club is circulating a petition in support. From Cascade (via Seattle Bike Blog):

NE 125th was chosen for this kind of project because too many drivers speed at over 40 mph – a deadly speed for the most vulnerable users of the road. More than half of collisions cause injuries on this stretch of road for drivers, passengers and bystanders. This is far higher than for most streets in the city. SDOT made the decision to move forward after careful study, and they will continue to collect data on the effectiveness of this safety project.Unfortunately, a group of well-meaning but misinformed people is pressuring our elected leaders to cancel this project. That is why it is so important to show our support for a safer street.

Click here for the petition

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Seattle Industry Opposes Road Diet

Once again plans for an SDOT road diet are upsetting someone. This time it’s the road diets planned for Airport Way and East Marginal that are being opposed Seattle’s industrial interests. At a forum sponsored by the Port of Seattle, PubliCola reports:

The city has proposed some version of a “road diet” on both streets. On East Marginal Way, which carries only about half of the cars it was built to accommodate in the 1960s, the city would reduce the number of lanes from six to four, plus a turning lane. On Airport, it would add bus bulbs and reconfigure parking to improve pedestrian safety; that proposal was generated by the surrounding community.

Longshore union representative Harold Ugles said accommodating more cyclists and pedestrians on either street would lead to job losses and traffic gridlock. “We’re under attack,” Ugles said. “What we’re trying to do is prevent gridlock, because gridlock drives away the jobs, it pisses off the public, and it’s a problem for everybody.” BNSF government affairs director Terry Finn warned grimly that if Seattle keeps adding “luxuries” like sidewalks and bike lanes, we’ll end up like Portland, a supposed dystopia where “income is 20 percent below that in Seattle.”

Seattle transportation director Peter Hahn tried to counter the dire warnings, noting that although opponents have predicted disaster every time the city has proposed a road diet, those predictions have never come true. “The harm that has been forecast did not occur.” And if it did, Hahn noted, the city could always just re-stripe the road for cars again. “It doesn’t cost millions to reverse it.”

Seattle Industry, a magazine and web site covering issues important to industry, laments that “SDOT’s top priority isn’t mobility – it’s safety, especially more safety for bicyclists and pedestrians.” (via PubliCola) The industry eBulletin suggests that this focus on safety threatens Boeing Field’s productivity.

However, as usual the impact of these road diets will be minimal to mobility and significant for safety. The lane rechannelization on East Marginal takes 5 lanes of vehicle traffic to 4, taking a lane away from the less-busy side of the road, which now has 3 lanes. The road diet on Airport Way makes the neighborhood of Georgetown safer for pedestrians by adding curb bulbs to allow pedestrians to cross safer. This closes a southbound lane to vehicular traffic (the less-busy side of the road, again) that is currently used for parking the 22 out of 24 hours in the day.

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