Four traffic lights on a stretch of road are spaced \(300 \mathrm{~m}\) apart. There is a 10-s lag time between successive green lights: The second light turns green \(10 \mathrm{~s}\) after the first light turns green, the third light turns green \(10 \mathrm{~s}\) after the second light does (and thus \(20 \mathrm{~s}\) after the first light turns green), and so on. Each light stays green for 15 s. Having watched this sequence for some time, you understand that there should be one best constant speed to drive to make all four green lights. You do not want to be delayed, but you are a cautious driver and want to drive as slowly as you can but still make it through all the lights on a single cycle.