It's a wet drizzly early Friday evening and the commuter exodus out of the city is its typical snail's pace. The roads are clogged (7 days a week, actually), flanked on all sides by brooding condo towers, scores of floors high. Tens of thousands of units mean thousands of cars on roads meant for 1980 capacities.
An emergency response vehicle with sirens blaring threads its way through the traffic, a lot slower than desired. Which leads any thinking person to dread the potential for disaster if and when several emergency situations arise simultaneously. Factor in the vertical component and... it is a scary thought.