My smart car is a narrow width, short wheelbase car. On the logging truck rutted right lane of I-5 in WA the car tracks poorly when I'm driving it. I end up driving on the high spots of the lane (far right or far left). If I let the car drift into a rut I have to grab the steering wheel tightly because the rut will slingshot the car. My solution was to lash down the steering wheel when flat towing. This keeps the car from drifting in the ruts when towing it. Normally it is not recommended, but in my case forcing the car to track straight makes it tow much better.
