In just about every way you can measure the topic, protected bike lanes have been linked to more and safer bicycling. There’s a logical reason for that: they’re protected from cars.

However, protected bike lanes aren’t only protected from automobile traffic; they’re also separated from sidewalks (at least via paint, if not curbs, bushes, trees, distance, or barriers). Naturally, this protects pedestrians from bicyclists, but in a number of obvious and subtle ways, this also protects pedestrians from cars. In some areas, the improvement is dramatic.

NYC DOT/Public DomainRegarding the NYC streets noted in the chart above, where protected bike lanes were introduced, Matthew Roe, the former senior safety planning and research manager at the NYC Department of Transportation, says: “There had been about one pedestrian fatality per mile for years on those streets. We saw huge, huge reductions.”

In that Streetsblog article, Michael Andersen of PeopleForBikes listed four reasons why protected bike lanes help protect pedestrians. Before sharing those, I’m going to run through some ideas from my own head as well.

Paul Krueger/CC BY 2.0

The most obvious point, I think, is that bicyclists and pedestrians no longer share a piece of (often narrow) infrastructure. Mixing relatively fast-moving bicyclists with pedestrians is somewhat like mixing fast-driving cars and slow-driving cars. Speeding is the more common and bigger traffic safety issue, but drivers can also get a ticket for driving too slowly, because the unexpected variation in speed is what causes a lot of the risk. At slower speeds, bicyclists aren’t nearly as dangerous as cars, of course, but the general safety issue is the same. If you don't force bicyclists and pedestrians onto the same infrastructure, bicycle–pedestrian collisions are reduced. (Of course, bicycle–pedestrian collisions are not the big threat to pedestrians. Car–pedestrian collisions are. But avoiding any collision is a good thing.)

NYC DOT/Public Domain

Another thing is that "more-complicated” infrastructure makes people pay more attention. It’s not hard to check both ways before crossing the street, but pedestrians sometimes get complacent and neglect to adequately do so before walking across. Even more disturbingly, many drivers do not see and even do not look for pedestrians as they make turns where pedestrians cross. The results are... well, you know the results. However, when there are car lanes, protected bike lanes, and sidewalks, people become more aware that they need to carefully look around before crossing another transportation route. Very simply, the greater awareness protected bike lanes bring to drivers is one of the key reasons bicyclists are safer, and the same goes for pedestrians. With a path for each mode of transport, the majority of people are subtly but effectively asked to be more attentive to others.

Protected bike lanes also often result in narrower car lanes. On the public safety front, narrower car lanes are a big win. Wide roads designed for cars to drive fast will result in people driving faster. Narrower roads will communicate to the driver that they should be more cautious and drive more slowly. Studies have found road design to be more influential than speed limit signs for influencing driving speed.

NYC DOT/Public Domain

Okay, jumping into Michael’s points, his first one was related to my point just above. He noted that “protected bike lanes shorten crossing distances.” Indeed, with fewer or at least narrower car lanes, pedestrians can much more easily get from one side to the other without being touched by a car. In the case of crossing the bike lanes, if there is an unexpected encounter, it’s much easier for a bicyclist and a pedestrian to avoid each other than a car and a pedestrian.

Michael’s second point is also an excellent one: “protected bike lanes make it easier to know which direction cars are coming from.”

Jacob/CC BY-NC 2.0

With more of the roadway chopped up and delineated for specific users, pedestrians can more easily focus on the crossing point at hand and can more easily examine the possible routes cars might be coming from when crossing the car lanes. “When you’re walking, it’s not the traffic you expect that poses a danger — it’s the traffic you don’t expect,” Michael aptly notes.

Dani Simons/CC BY-NC-SA 2.0

The essence of Michael’s third point is visibility. Very well emphasized in the bicycling world (and general transportation safety world) is that one of the dangers people bicycling on sidewalks face is that they are more often shielded from drivers and a driver may not see them while turning across their path... until it is too late. A similar but perhaps less obvious point is that pedestrians (and joggers) can be shielded in the same way. If a driver has to cross a protected bike lane to get to where he or she is headed, he or she will have a clearer view of where bicyclists might be coming from, but also a clearer view of where pedestrians might be coming from.

Another matter of "visibility" that Michael didn't mention but is also very important is that, the more bicyclists and pedestrians there are on the street, the more drivers take note that they need to watch out for bicyclists and pedestrians. Seeing more people on the street makes you more aware that people are on the street. Obvious, but often overlooked. This is surely one of the reasons that bicyclist fatalities and injuries drop, on a relative basis if not an absolute basis, as bicycling rates go up.

Paul Krueger/CC BY 2.0

Michael’s final point is the least obvious, in my opinion. It is: “protected bike lanes reduce traffic weaving.” This is an excellent point that wouldn't have crossed my mind. It’s got to be one of the most dangerous actions for pedestrians: a driver is switching lanes while approaching a crosswalk and doesn’t see the shielded pedestrian until the last minute. As Michael puts it: “Another maneuver that endangers people walking is the ‘zip-around’: people swerving their car from one lane to another to get around a stopped car, only to realize the other driver had stopped to yield to someone in the crosswalk.” Almost all of us have seen close calls from this, and I’m sure many have seen worse. Protected bike lanes help here again when they reduce the number of car lanes (and especially “mixed traffic lanes”). “Once zip-arounds become impossible, people driving simply queue up to wait their turn — and people walking are, once again, the biggest winners.”

As we can see, there are a lot of obvious as well as subtle reasons why protected bike lanes help to protect pedestrians. Now that we have run down so many, can we have protected bike lanes on all the roads?!