# Bicycles riding contraflow **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [September 25, 2015, 10:14am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467 "2015-09-25T10:14:45Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![cmosdes](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@cmosdes](https://boards.straightdope.com/u/cmosdes)\ **Post date:** [September 30, 2015, 10:49pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/21 "2015-09-30T22:49:12Z")
> [@sbunny8](#): > > Yes, and it gets worse from there. > > I’ll use higher number which I think are more realistic. Let’s say the bike is going 12mph and the cars are going 36. When riding the same direction, closing speed is 24. When riding in opposite directions, closing speed is 48. Exactly double. So the drivers’ reaction time is cut in half. > > Now suppose the trip is 3 miles long and the cars are 110 yards apart. The bike will take 15 minutes to complete the trip. If it’s traveling in the same direction as the cars, 96 cars will pass the bike. But if the bike is riding against traffic, 192 cars will pass it going the other way. So the number of encounters has also doubled. > > And if there does happen to be a collision between the bike and a car, it will happen at double the closing speed, increasing the level of damage and/or injury plus risk of death. And kinetic energy increases by the square of the velocity, so the energy transfer is higher by a factor of 4. > > So riding against the traffic… > cuts the drivers’ reaction times in half > AND doubles the number of passes > AND quadruples the damage of any impacts. > > It seems to me this shows that riding against traffic is SIXTEEN TIMES more dangerous than riding with traffic. This completely ignores the ability of the cyclist to see the oncoming vehicle and react to it. Let me be extremely clear. I’m _not_ advocating for cycling the opposite way. As other have pointed out, this one advantage isn’t enough to offset the other drawbacks. Seeing the oncoming traffic can be a huge benefit, but not to the point of making it a good idea. I would have rather seen an answer to why cycling opposite of car traffic is a poor choice for the law and custom, rather than just saying it is against law and custom. People in here did a far better job of doing that. ---
**Author:** ![sbunny8](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@sbunny8](https://boards.straightdope.com/u/sbunny8)\ **Post date:** [October 1, 2015, 12:52am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/22 "2015-10-01T00:52:59Z")
> [@cmosdes](#): > > This completely ignores the ability of the cyclist to see the oncoming vehicle and react to it. Let me be extremely clear. I’m _not_ advocating for cycling the opposite way. As other have pointed out, this one advantage isn’t enough to offset the other drawbacks. Seeing the oncoming traffic can be a huge benefit, but not to the point of making it a good idea. That’s only an advantage if you assume that the riding-with-traffic cyclist doesn’t have a rear-view mirror. I have one on my left handlebar. Admittedly, the visibility is less than 100% but I also have twice as much time to react, compared to a riding-against-traffic cyclist, so that makes up for limited visibility. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 1, 2015, 2:29am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/23 "2015-10-01T02:29:30Z")
React how? If our counterflow cyclist sees a car coming straight at him (which is what the cars are after all supposed to be doing), just what can he do to react? ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [October 1, 2015, 3:35am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/24 "2015-10-01T03:35:11Z")
> [@Telemark](#): > > It’s actually a one lane road, there’s parking on both sides. It would be safer if there was parking only on the opposite side of the road from the bike path, but no way would they give up that many parking spaces around here. It would also be more sensible to put the bike lane between the parked cars and the curb, but people for some reason resist that. How about a curb line for the parked cars, then a bike lane, then another curb to the sidewalk or grass? That way the bike lane is actually separated from the auto flow completely, but the cars can still park against a curb. > [@Chronos](#): > > React how? If our counterflow cyclist sees a car coming straight at him (which is what the cars are after all supposed to be doing), just what can he do to react? Eat a curb. Yeah, there’s not a lot of reaction time unless the car is weaving and generally being noticeably unsafe. Just a generic driver who happens to be inattentive is not going to stand out until it hits you, from the front or from the rear. A wild driver is going to give the facing driver an early warning, a non facing driver needs to rely on sound and maybe a mirror. My experience with a handlebar mirror was it was tricky to keep it aimed behind me to see the oncoming cars. Too easy to bump off target and have to readjust, which is tricky while moving and probably not safe. Then I broke my mirror off. ☹ ---
**Author:** ![Mart44](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mart44](https://boards.straightdope.com/u/Mart44)\ **Post date:** [October 1, 2015, 3:49pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/25 "2015-10-01T15:49:12Z")
I feel uncomfortable riding without a handlebar mirror. I have broken mirrors from time to time (usually when off-road riding) and miss it greatly when it’s not there. I usually keep a spare so I can replace a broken one. The Zefal Dooback Folding Mirror is the best one for straight handlebars in my opinion. Gives quite a large viewing area. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [October 1, 2015, 4:30pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/26 "2015-10-01T16:30:38Z")
> [@Irishman](#): > > It would also be more sensible to put the bike lane between the parked cars and the curb, but people for some reason resist that. How about a curb line for the parked cars, then a bike lane, then another curb to the sidewalk or grass? That way the bike lane is actually separated from the auto flow completely, but the cars can still park against a curb. They did a great job nearby although Streetview hasn’t caught up yet - [Google Maps](https://www.google.com/maps/@42.364817,-71.1099373,3a,75y,251.03h,76.49t/data=!3m6!1e1!3m4!1sg1_q3YXuuadnHFp0BDGAGA!2e0!7i13312!8i6656!6m1!1e1) They took a three lane, one way artery and turned it into a two lane plus a dedicated bike lane that is separated from both the road and sidewalk by curbs. The bike lane is one way as well, and has separate street lights for that lane that are different than the ones for the cars. It’s ideal, even if you have to shoo walkers and runners out of the bike lane - they’re supposed to be on the sidewalk. But it was major construction and quite expensive and disruptive to commuters for a while. ---
**Author:** ![qazwart](https://avatars.discourse-cdn.com/v4/letter/q/5fc32e/32.png) [@qazwart](https://boards.straightdope.com/u/qazwart)\ **Post date:** [October 1, 2015, 8:40pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/27 "2015-10-01T20:40:19Z")
> [@Chronos](#): > > React how? If our counterflow cyclist sees a car coming straight at him (which is what the cars are after all supposed to be doing), just what can he do to react? Screaming like a banshee and covering their eyes before they hit your car. ---
**Author:** ![qazwart](https://avatars.discourse-cdn.com/v4/letter/q/5fc32e/32.png) [@qazwart](https://boards.straightdope.com/u/qazwart)\ **Post date:** [October 1, 2015, 8:47pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/28 "2015-10-01T20:47:05Z")
> [@Telemark](#): > > They did a great job nearby although Streetview hasn’t caught up yet - [Google Maps](https://www.google.com/maps/@42.364817,-71.1099373,3a,75y,251.03h,76.49t/data=!3m6!1e1!3m4!1sg1_q3YXuuadnHFp0BDGAGA!2e0!7i13312!8i6656!6m1!1e1) > > They took a three lane, one way artery and turned it into a two lane plus a dedicated bike lane that is separated from both the road and sidewalk by curbs. The bike lane is one way as well, and has separate street lights for that lane that are different than the ones for the cars. It’s ideal, even if you have to shoo walkers and runners out of the bike lane - they’re supposed to be on the sidewalk. > > But it was major construction and quite expensive and disruptive to commuters for a while. Interestingly, in Europe, they’re going a completely different direction: Cars, bikes, and pedestrians all in the street. And, they remove all traffic control signage too. No stop signs. No yield signs. No traffic lights. This forces everyone to stay on their toes and drive or move more carefully. The theory is that most accidents are caused by people assuming things because it was that way previously. A driver makes a right turn hits a pedestrian crossing a street because the driver doesn’t have a stop sign, and the cross traffic does. Or, a driver running a stop sign because the six previous intersections didn’t have. Speeding down a street because it’s straight, and you have the right away. If danger lurks at every corner, you’ll be much more careful about driving or walking. ---
**Author:** ![zedzed7](https://avatars.discourse-cdn.com/v4/letter/z/ec9cab/32.png) [@zedzed7](https://boards.straightdope.com/u/zedzed7)\ **Post date:** [October 3, 2015, 7:16pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/29 "2015-10-03T19:16:18Z")
the main reason bikes should go go against the flow is the same reason walkers do ~~seeing the on coming traffic. and given enough time to avoid injury. i have personal experience with this with having been forced into a curb by a distracted motorist and the skin flayed off one arm. i ws lucky not to have been injured more seriously. quoting figures on distracted walkers is ignoring the main problem of distracted drivrers that now outstrips the old problem of drunk drivers. its time to change the law for safty reasons. ---
**Author:** ![Iknowstuff](https://avatars.discourse-cdn.com/v4/letter/i/a4c791/32.png) [@Iknowstuff](https://boards.straightdope.com/u/Iknowstuff)\ **Post date:** [October 4, 2015, 11:38am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/30 "2015-10-04T11:38:53Z")
All this talk of relative speed of with traffic or against traffic bikes compared to cars is beside the point. The danger of head-on collisions is small. People ride against traffic because they’re worried about that, but the true danger comes fro ---
**Author:** ![Iknowstuff](https://avatars.discourse-cdn.com/v4/letter/i/a4c791/32.png) [@Iknowstuff](https://boards.straightdope.com/u/Iknowstuff)\ **Post date:** [October 4, 2015, 11:48am UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/31 "2015-10-04T11:48:38Z")
All this talk of relative speed of biking with traffic versus against traffic compared to cars is beside the point. The danger of head-on or rear-end collisions is small. People ride against traffic because they’re worried about cars hitting them from behind, but the true danger comes from motor vehicles making turns. If you’re riding against traffic they won’t see you. Even if you’re riding slowly, you’re still twice as fast as a pedestrian, and the motorist will claim you ‘came out of nowhere’. Cecil didn’t stress this point enough. Also, those folks in Japan who get mad at the with traffic cyclist for not moving over have a lot of nerve. Give 'em some American style verbal thrashing. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 4, 2015, 7:47pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/32 "2015-10-04T19:47:04Z")
> [@](#): > > Quoth **zedzed7** : > > the main reason bikes should go go against the flow is the same reason walkers do ~~seeing the on coming traffic. and given enough time to avoid injury. That’s the main reason to ride _with_ the flow, because it gives you more time to avoid injury. Again, if you’re going the wrong way, and you see a car coming at you, what good does it do to see it? What can you do to react? ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [October 5, 2015, 4:21pm UTC](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467/33 "2015-10-05T16:21:50Z")
It potentially gives you a view of the driver’s eyes to see if they notice you. If you think they aren’t paying attention, you can ditch to the sidewalk/grass. However, it may be difficult to tell if they see you, and so unless they are veering wildly, you can’t tell if they will avoid you or not until they hit you. Just like from behind. The disadvantages are they can’t slow down to time their pass to match other traffic, they are less likely to see you around obstacles or if they are coming out of driveways, and if they do hit you, the speed differential will be significantly higher. [Previous page](https://boards.straightdope.com/t/bicycles-riding-contraflow/732467.md?page=1)