Transportation agencies are at odds over the use of road diets for traffic calming efforts. Some view them as a safety measure, while others believe they hinder traffic flow and emergency vehicle access. Recent federal policy changes indicate a shift away from funding projects that reduce lane capacity for vehicles. Various cities have experienced differing outcomes with road diets, prompting debate on their effectiveness.
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Road diets, long thought a critical tool in the traffic control arsenal, are falling out of favor with transportation agencies at the federal, state and local level.
The federal department of transportation has reversed course on the longtime safety design concept of reduced lane capacity, or "road diets." Not only are some states also wanting to end lane reductions, but cities in Texas, California and Washington have worked toward a similar outcome. Road diet advocates see the movement as forfeiting a critical tool for slowing down drivers.
This spring, when the application window for the federal Safe Streets and Roads for All program opened, it was considered by many to be tight.
Criteria for the DOT's $1 billion grant program read that less consideration would be given to safety projects that reduce lane capacity for vehicles.
According to Streetsblog, in the past, the funds have gone to a mix of planning grants and hard infrastructure projects "aimed at saving lives."
Historically, those projects include bike lanes, sidewalk expansions and road diets.
But the new grant criteria read that projects including infrastructure reducing lane capacity for vehicles would be viewed less favorably by the department.
Traffic reduction advocates fear the agency will drop road diets from its most critical safety program. In doing so, say advocates, the fed will forfeit one of its most important tools to save lives in and out of automobiles.
"Excess road capacity leads to excess speed," Chris Forinash of design firm Nelson\Nygaard, told Streetsblog.
He believes the much-needed modernization of many roads must "include how we allocate our public right of way for maximum public benefit."
Others are concerned that safety might take a backseat to maintaining space for cars no matter how busy the road. But road diet opponents believe traffic calming methods only serve to bog drivers down and can threaten the effectiveness of emergency vehicles.
Explaining Road Diets
For many years, the DOT has recognized road diets or road rebalancing as a way to save lives. With the design concept, corridors are reconfigured to make more room for bike lanes, sidewalks, bus lanes, train lines or other infrastructure.
The goal is to make more room for people outside cars and to encourage motorists beside them to slow down, said Streetsblog.
Road diets encourage people to leave their cars at home and streamline turning movements for drivers that frequently cause back-ups.
Streetsblog said studies show the concept can actually decrease congestion often without adding extra traffic to adjacent side streets.
"Studies show that converting a four-lane road to three lanes can cut crashes as much as 47 percent," said the blog.
Simply narrowing existing lanes from a highway-style width of 12 ft. to a neighborhood-appropriate 9 ft. can cut crashes significantly, said Streetsblog.
These approaches can create room for other modes, linear parks, outdoor dining and retail, it said.
Road diets that reclaim a lot of lanes like highways-to-boulevards conversions, even housing and businesses result.
Why Some Favor Traffic Calming
Orange County, Fla., rationalized the road diets by explaining that they are an effort to keep up with shifts in modes of transportation. The county's busiest thoroughfares were developed back when cars ruled the road, the agency said.
"But in recent years, people have changed how they get around. Mass transit, bicycles, scooters and other micromobility devices have become more popular."
As a result, more people travel along these busy roads rather than in the middle of them, said the county.
"In order to keep up with these shifts, Orange County Public Works is retrofitting certain roads to accommodate new methods of transportation."
At the same time, the county hopes to protect a growing number of pedestrians by using a road diet strategy. The county believes the benefits include:
• reduction of rear-end and left-turn crashes due to the dedicated left-turn lane;
• reduced right-angle crashes as side street motorists cross three versus four travel lanes;
• fewer lanes for pedestrians to cross;
• opportunity to install pedestrian refuge islands, bicycle lanes, on-street parking or transit stops;
• traffic calming and more consistent speeds; and
• creation of a "complete streets" environment that better accommodates the needs of all road users.
In explaining its preference for road diets where they make sense, the city of Raleigh, N.C., liked that the move allowed for additional bike lanes. It also resulted in the creation of a pedestrian refuge island "allowing safer connectivity to transit and the greenway trail along the street," said the city.
"Adding these components provide safety measures for both bicyclists and pedestrians."
The city of Kansas City, Mo., saw money savings when it put one busy roadway on a road diet and installed a gas line.
The road was reduced from two lanes to one in either direction. A shared turn lane, pedestrian crossings and on-street parking spaces also were added.
In an Associated Press article, city planners said road diets are almost automatic whenever a street is up for repaving.
Bobby Evans, an urban planner of the Mid-America Regional Council, terms the strategy "a smashing success."
He believes its's one of the most effective tools at reducing speed, crashes and injuries.
"In the architectural world you'd call it environmental determinism," Evans said. "You want to make it so they don't feel comfortable going too fast. You're really not slowing them down. You're bringing them back to the speed limit."
Philadelphia, Pa., saw a 19 percent drop in injury crashes. Portland, Ore., had a 70 percent decline in vehicles traveling at least 10 mph over the speed limit.
The AP reports the average speed in Fort Lauderdale, Fla., fell by 5 mph on some roads within months.
Leah Shahum of street safety advocacy non-profit Vision Zero Network said road diets are inexpensive and supported by years of research.
Concept Flaws
Jay Beeber, NMA policy executive director of the National Motorists Association, would beg to differ.
Beeber believes most road diets represent "an ill-advised effort to force vehicles off the road."
He said the number of vehicles may decline on dieted roads, but then surrounding roads have to absorb the traffic.
"Those cars have to go somewhere," he said. "Cars are like water. They seek their own level."
The fed cited concerns about delivery and emergency vehicles among its reversal of policy on road diets.
Research done in Iowa found that there was no level of congestion slowing down EMS or fire trucks where road diets were implemented.
But skepticism regarding traffic calming measures such as road diets are not new among major cities, according to the AP story.
After years planning to repurpose pavement, removing vehicles lanes and making way for bikes and pedestrians, San Antonio, Texas, reclaimed the road.
During the pandemic, Culver City, Calif., implemented a road diet to prioritize walking, biking and transit.
But, AP reported, when cars returned and traffic backed up for miles, the city reversed the plan.
Some residents sued in Vancouver, Wash., saying the city should have put its road diets up for a public vote.
"I've seen people passing in the shoulder or the bike lane," said Justin Wood, one of the opponents. "It creates more opportunity for conflict."
Even traffic designers, including Evans in Kansas City, have had to admit that road diets can't stop all reckless drivers.
"If you are bound and determined to go 12 miles over the speed limit on a three-lane road, you're going to have to engage in some dangerous driving," said Evans.
The USDOT said forcing travelers into more constrained spaces "can lead to crashes, erratic maneuvers."
The agency told the AP, it also can result in "a false sense of security that puts everyone at risk."
The update reflects the department's concerns about the safety hazards associated with congestion, said the agency. In fact, the NMA has long believed that traffic calming measures such as road diets only serve to obstruct traffic flow.
In a 2020 post on the topic, Sheila Dunn, communications director, said the real solution is to upgrade and improve traffic handling capabilities.
"This means implementing physical improvements, as well as raising speed limits and synchronizing traffic controls to accommodate actual vehicle speeds."
Dunn said if main streets provide convenient access, motorists will use them instead of alternate routes through residential neighborhoods.
"Motorists deserve roads that not only work, but can also be put to work," she said.
"That means allowing people the freedom to travel to the destination of their choice when they want with the least amount of interference."
NMA considers that freedom a fundamental principle of the American way of life.
"It also means keeping roads open for the movement of goods and services that is essential for society as a whole," said Dunn.
Programs that encourage traffic calming and road diets are designed to severely limit motorized traffic in city centers. These design concepts in fact actually wind up diminishing driver mobility, said Dunn.
Texas wants to bar cities from narrowing roadways to create wider sidewalks or protected lanes for cyclists and buses. The Houston Chronicle reported this spring that the bill is meant to stop the implementation of vehicle bans, street closures or congestion pricing.
When the bill was introduced, the goal was to prohibit any city from imposing a fine on any form of transportation. CEG
Lucy Perry
Lucy Perry has 30 years of experience covering the U.S. construction industry. She has served as Editor of paving and lifting magazines, and has created content for many national and international construction trade publications. A native of Baton Rouge, Louisiana, she has a Journalism degree from Louisiana State University, and is an avid fan of all LSU sports. She resides in Kansas City, Missouri, with her husband, who has turned her into a major fan of the NFL Kansas City Chiefs. When she's not chasing after Lucy, their dachshund, Lucy likes to create mixed-media art.
Read more from Lucy Perry here.
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