Many local government leaders across the country know the types of street designs that reduce the number of severe crashes, but they keep delaying the changes because they’re waiting for money. Waiting for a big federal grant. Waiting for a full reconstruction project. Waiting for the perfect, permanent solution. But while Americans wait, people keep getting hurt.
There’s a better way, and it doesn’t require tearing up a single road.
Road diets repurpose space that already exists. By narrowing or reducing car lanes on overly wide streets, cities can carve out protected bike lanes, pedestrian refuges, and calmer traffic conditions—without major reconstruction. But here’s the real choice cities face: act now with quick-build methods to establish a safe network across dozens or even hundreds of blocks, or wait decades for funding to deliver premium concrete infrastructure on just a handful of blocks.
This isn’t an argument against quality. Bike lanes protected by concrete or landscaped islands are excellent. But a gold-standard lane on one street does nothing for the person trying to bike safely ten blocks away. Coverage matters, and quick-build methods make coverage possible right now, within a single generation.
Capture the territory first, and harden it over time.
What Road Diets Do
A road diet reorganizes street space by narrowing and/or reducing regular car lanes to add protected bike lanes without major reconstruction. Road diets deliver measurable improvements beyond bike lanes. Federal Highway Administration and U.S. Department of Transportation data and studies show they benefit drivers, pedestrians, and the overall street environment:
Overall benefits. Road diets reduce total crashes by 19–47% on average when converting a four-lane undivided road to a three-lane configuration with a center turn lane. This includes reductions in rear-end, left-turn, and sideswipe crashes due to fewer conflict points and better separation of turning traffic. An analysis of 45 road diet sites in California, Iowa, and Washington found a 29% reduction in total crashes.
Driving benefits. Narrower lanes and fewer through lanes encourage more consistent speeds, reduce aggressive passing/weaving, and minimize “accordion” stop-and-go patterns. This can improve traffic flow for drivers in many cases, with dedicated turn lanes easing left-turn delays. Reduced speed differentials also lower crash severity.
Walking benefits. Fewer lanes to cross means shorter exposure to moving traffic and reduced crossing times. Road diets create opportunities for pedestrian refuge islands, which can cut pedestrian crashes by up to 46%. They also support curb extensions or wider sidewalks for added safety.
Two Types of Protection
The two main protection types below use the same amount of physical space.
Concrete-protected bike lanes
Use raised concrete curbs or buffers (typically 6–8 inches high) for separation.
More durable and effective at preventing vehicle incursions.
Require more equipment, forming, pouring, and intersection work, so costs are higher.
Paint and flex-post bike lanes
Use painted buffers with flexible delineator posts (usually spaced every 20 feet).
Quick to install (often in weeks), inexpensive, and adjustable or removable if needed.
Provide good visual and physical separation for lower speeds/traffic volumes.
NACTO is a great resource for illustrations like the ones below. This is just one example of how a wide, one-way street can be converted using a quick-build approach.
What Your Budget Can Buy
Below are three different budget examples to show the difference in coverage, based on recent project costs in places like Richmond, VA. These assume protected bike lanes on both sides of the street and a typical city block length of about 300 feet:
With a $50,000 budget:
Concrete: 1–2 city blocks
Paint & flex posts: 15–20 city blocks
With a $200,000 budget:
Concrete: about 5 city blocks
Paint & flex posts: about 50 city blocks
With a $1,000,000 budget:
Concrete: roughly 20–40 city blocks
Paint & flex posts: about 300–500 city blocks
Quick-build approaches enable generational improvements within a single generation. Premium-only strategies can take generations to achieve meaningful coverage.
Cities can start with paint and posts to establish a basic network quickly, demonstrate usage, and then harden high-priority segments with concrete as funding allows. This staged approach gets more streets safer for everyone sooner rather than delaying everything for premium designs.
This makes so much sense to me! But. Having sat through a bunch of local debates on exactly this type of thing (which I've been reporting on icymi), I know what our engineers will say: "Dilineators are bad because have to maintain them, and our snowplows willl hit them, which is annoying and expensive for us. But people will *feel* safer using dilineator-protected lanes and will bicycle more, which is bad, because posts aren't real protection, so if someone hits them, we get sued. Whereas if we do nothing at all nobody sues us even though it's dangerous as hell. Because the danger keeps everyone from even trying. So everyone stays in their cars, the way we like it." (OK, they'd put it a little differently, I am peering into their brains. I have been listening to them a lot.)
As I've been writing increasingly about how CYA dominates road safety (fear of lawsuits is the guiding principle, not fear of death/injury) I wonder how we get past this. Any ideas?
Seattle has done all this and is doubling down to do more and more. Meanwhile, our car accidents and our pedestrian fatalities and our bicycle accidents and fatalities continue to rise. Meanwhile, our congestion and our pollution also continue to rise because, partly because cars are spending far longer in traffic due to the changes.
High traffic calming bumps have been applied to a major two-lane thoroughfare that runs about 2 miles from the shopping neighborhood (with a major grocery store) to where I live. I am now seeing traffic backed up a mile at rush-hour and I sometimes end up going 10 mph because the bumps are so steep and so close to each other. Bicycles almost never used this road because there are speed bumps and a dedicated bike lane one block over. When they insist on using this road, it adds another 20 minutes to the commute because there is no shoulder and so you must either go at the speed of the cyclist or go into the left lane to pass them.
If you put a bus on a road like this with only two lanes each time the bus stops it also backs up traffic. On the one major north end east west thoroughfare, which was four lanes, we now have a 3-lane road with a center turn lane and bike lanes and the commute is 25 minutes longer. No one has seen a bicycle on this street in 20 years. Bike lanes were put in on a portion of this road well over 10 years ago and and it was already clear that bicycles don’t want to go on the street as they were always empty. But the bike lane fanaticism prevailed.
A piece that has been left out of the traffic accident story is the public safety element. During pandemic, we lost 400 state patrol and 300+ police within the city limits who used to enforce traffic laws. It has been well known in Seattle since 2020 that you can do anything you want and you will not get a ticket. I think cities are unique and that one size fits all solutions are not the one size fits all solution!
https://www.kuow.org/stories/seattle-s-traffic-deaths-are-climbing-one-city-council-member-wants-an-audit-to-find-out-why