Driving on the white line
 

I just read a comment about hypermilers "driving on the white line" to reduce rolling resistance and promote better FE. Unfortunately I couldn't find any discussion of it on the internet.

So to bring it up here... has anyone actually tried this? I wonder what the actual difference in rolling resistance is.

Driving on the white line
 

When I encounter rain, I drive on the "white line." That is, I drive on the higher, more elevated line (wheel track) where the water is not pooling. I find the center line (wheel track) to be where water usually pools.
In addition, I avoid letting the wheels drift into the very center of the road where oil drips for wet road conditions ("maximize" road adhesion).
[I am interested in what motorcyclists do about the center of the road and if oil dripping from vehicle engines onto the road is something to note.]

That is for wet conditions, and I do not intentionally drive on the white line for fuel economy reasons. However, I feel that there is an advantage to driving on the center lane, where the worn road is more polished and may contribute to less rolling friction.

I think the nickname for it is "Ridge Riding"

On brand new roads, it sometimes seems like you can feel a difference, less rolling resistance with a wheel on the line. On roads that have been in service a couple years though, the centre ridge your other wheel goes on ends up rough, uneven, and covered in oil drips, so I think you gain more RR that side than you lose on the line side, and despite being rougher, I think you're at risk for extended stopping distances in wet weather from the oil and tire crumbs. Seems the "grooves" get polished more smooth here.

In dry weather, often the grooves are smoother, so use those.

I'll sometimes ride to the right side to signal traffic that I'm going slow. They're more likely to just pass instead of tailgating me.

In the rain, I choose whatever has the least water, within the span of the lane. If that's partly on the white line, I'll ride there.

Actually, reading basjoos's post about the airspeed indicator, hanging over to the right, on a single lane each way road, would seem to have the advantage of staying more out of the "negative draft" of oncoming traffic.

Sure. I notice that effect, and move over to the right to try and avoid it, regularly.

Doh, meant right, that other left :D editing... it's from learning to drive in UK then coming over here...

It could possibly help when you've got thick lines, not thin spray-painted lines. Those are the same lines that bicyclists avoid due to low traction. They are slippery, especially when wet.

Another thing to think about though, when grooves are pronounced, like a 2 inch hump in the middle, that's like having the car lowered 2 inches when riding in them, or having it lifted 4 inches when you ride the ridge and line.

I am interested in what motorcyclists do about the center of the road and if oil dripping from vehicle engines onto the road is something to note.


I've been riding motorcycles since the late seventies and it used to be common knowledge to stay out of the center of the road because of oil drippings. When I am riding alone I always run left of center so I will be in the other drivers rear view and when riding in a group I and most other bikers alternate one left of center one right of center and so on. Even though I have been riding for 30 years I still get a little nervous when it starts to rain because of oil from cars and from the asphalt itself. Oil and water can make a very dangerous situation.