I was just sent a link to this by a good friend of mine and avid commuter cyclist - Ellie Grace. I just fell in love with the concept- although still unsure how the chalk is administered, if it creates any drag on the wheel and how long the chalk lasts- nevertheless- a fantastic idea. Here is some text copied from the designer's website:
Contrail is a tool for developing bicycle communities. As you ride, contrail leaves a faint chalk line behind your bike. The goal is to encourage a new cycle of biking participation by allowing the biking community to leave a unique mark on the road and to reclaim this crucial shared space.
The old cycle: More cars on the road --> more percieved danger for bikers --> fewer bikers on road --> even more cars on the road.
The new cycle: A few bicyclists ride with contrail a couple times per week --> faint lines on the road inspire curiosity and remind bikers where it's safe to ride --> new bikers are encouraged to ride and use contrail --> contrail lines get brighter as community grows.
We like how doobybrain.com phrased it:
By using this device, bicyclists will have a clearer path on which to ride safely and out of the way of vehicular traffic. At the same time, as more bicyclists using the Contrail go over a line created by a cyclist before them, the line gets brighter allowing drivers to clearly see a marked bike path where there might be none. It's sort of similar to what happens when a dirt path appears in a grassy field after lots of people have taken the same shortcut over a period of time.
I just want to know where and when I can buy one.