When the 66 Express Lanes opened a year ago, officials promised the tolls would mean a smoother ride on the interstate, a major east-west thoroughfare from Northern Virginia into the District that is infamous for its headache-inducing congestion. The state’s promise — less congestion and faster travel times during rush hour — has been fulfilled for many commuters able to pay or carpool, but the new toll system has had an adverse effect for many of the remaining road users. For some commuters, the rush-hour period has simply shifted later — outside the toll hours — and dumped them onto...