As rush hour commuters know, traffic congestion remains a troublesome problem in many metropolitan areas – and how to put the breaks on it has eluded policy makers for decades. But at least in two cities, those of Los Angeles and Houston, a novel solution seems to be working. The concept involves something called the high occupancy toll lane, or hot lane for short, which charges solo commuters a variable toll for using what used to be hov lanes. This toll increases as more traffic pours on to the restricted hot lanes, thus ensuring they never become too congested. Having already shown itself to be a good revenue raiser, time will tell if the hot lane concept proves to be a hot idea for easing traffic congestion.