M56, 11pm, DRLs only.

[speedking31]

Was travelling along an unlit section of the M56, very light traffic. In the distance could see a vehicle in lane 1 that appeared to be unlit. Sometimes failed trailer lights might make the vehicle lights obscured. As I got closer (they were doing ~65 mph) I could see it was a car showing no lights to the rear. I put main beam on on approach. Went past and could see that front DRLs only were on. Pulled in and turned my lights on and off to flash rears. There was no response. I pulled away again and all the time it was in sight the vehicle's lights were not turned on.

Was there any other signal or action I should / could have taken?

[speedking31]

As I intimated I think I could only see the car as it obscured the lights of vehicles in front of it rather than seeing the actual car itself. Distracting as you try to work out what it is up ahead.

[speedking31]

Because it wastes twice as much electricity = fuel = lower mpg.