UxSight has unveiled a gadget called an "Land Meter" which promises to tell you exactly how your car, truck, or tractor is tilting. Powered by your cigarette lighter, the gadget sits on your dashboard as a constant reminder of how off-kilter you are.
The inclinometer measures 124x57x80mm and weighs slightly less than 200g. It comes with a self-adhesive bottom, so it shouldn't fall off when you're hitting a 40 degree roll. The shop says it's " ideal for 4x4's Tractors Lawn Mowers etc".
If you spend a lot of time on tilted roads then you might find it useful. It costs £12, and it's available now from UxSight. Shipping is an extra £4 or so on top, taking the grand total to £16.