In short, an overwhelming amount of real world data and experience shows that it is more efficient, safer and better for almost every user.
I have written on this before and have spoken on the topic many times, but since this issue is current I thought I would revisit the topic. Often people look at something and claim common sense would dictate it was the incorrect decision. In reality the correct solution is counter intuitive and the “common sense” actually represents “common ignorance.” Two of these incorrect assumptions I commonly hear are whether a 4 to 3 conversion is better and whether bike lanes should be inside right turn lanes and intersections. As it turns out the correct solutions to both are crystal clear. Ignorance can be due to a lack of education or willful, I do my best to respect and address the first; I can’t do anything about the second. Most people upon learning the facts can make an informed choice (as did the neighbors and businesses on 2nd street), however there are still a few people that will remain willfully ignorant…
Real world data: https://safety.fhwa.dot.gov/provencountermeasures/fhwa_sa_12_013.htm
Here are the facts on 4 to 3 road diets:
- Decreasing vehicle travel lanes for pedestrians to cross, therefore reducing the multiple-threat crash (when one vehicle stops for a pedestrian in a travel lane on a multi-lane road, but the motorist in the next lane does not, resulting in a crash) for pedestrians,
- Providing room for a pedestrian crossing island,
- Improving safety for bicyclists when bike lanes are added (such lanes also create a buffer space between pedestrians and vehicles),
- Providing the opportunity for on-street parking (also a buffer between pedestrians and vehicles),
- Reducing rear-end and side-swipe crashes, and
- Improving speed limit compliance and decreasing crash severity when crashes do occur.
Typically these conversions can easily be done for streets with less than 20,000 vehicle trips per day. In the uptown area the portion that was converted to 3 lanes has less than 10,000 vehicle trips per day. Thus it is a really easy decision. Interestingly there was plenty of room to keep 4 lanes and add bike lanes, so we did not remove a lane to “add” bike lanes, but rather made two separate choices, we added bike lanes and we made a better road by converting 4 to 3.
Here is yet another article explaining why 4 to 3 conversions are so beneficial to all users.
The main benefit of a 4-to-3 conversion has to do with safety and quality of life. While safety improves for everyone, including drivers, it dramatically improves for the most vulnerable road users, people who live and walk along these main arterials. At first, a simple change in the lane configuration may not seem like much, but to understand why they make such a big difference, think about the different road users and how they behave in each of these situations.
First, from a driver’s perspective: how you behave on a 4-lane configuration is really different from a 3-lane configuration. With two lanes in each direction, drivers are always thinking about passing each other. Driving down the road, you’re constantly scanning the cars ahead of you to see if they are slowpokes, or if they’re making a (dreaded) left turn. Cars are continually switching back and forth between the two lanes, glancing over their shoulders to see if the person in the next lane will let them in, speeding around turning and slowing cars and trucks. (For a good example, drive down Hennepin Avenue pretty much anytime.) This kind of situation means that car drivers aren’t paying much attention to the sidewalks, crosswalks, or looking out for bicyclists. This configuration facilitates speeding, and creates lots of dangerous automobile movements especially at intersections.
Lastly, we didn’t just choose a one size fits all solution, rather we studied the stretch and made sure it addressed. The conclusion was that this solution best addressed our issues of high crash rates, speeding, left turns, and pedestrian & bike safety. It certainly hit home when a friend of mine was seriously injured crossing the street.
Another questions is, “Why place bike lanes on the inside of right turn lanes?” The short answer is because it saves bicyclists lives, even if it is counter intuitive.
The most common bicycling crash caused by drivers is referred to as a right hook. This is a right hook:
2nd street SW and West Circle drive is one of the worst locations for right hooks in the city of Rochester because Westbound drivers arrive on red, look to the South and then turn right on red, never checking their right side. I have been hit twice there by inattentive drivers.
Community leaders, engineers, and cyclist got together and tried to figure out how to prevent these crashes and that is how the bike lane inside right turn lane came to be. As an avid cyclist I would claim this design should be common sense.