You’re sitting in your car barely moving or inching on your way to work in the morning, seething, and looking at what seems to be a huge parking lot. It doesn’t help knowing it’s supposed to be an expressway, and imagining the traffic flow in the regular roads in the city must be moving faster. Of course, you’d end up cursing the government for not building more expressways. But is building more lanes the solution?
Most of us go to work in the morning and go home in the afternoon or evening. A few who work on 24-hour facilities go to work on 8-hour shifts like 7 A.M. – 3 P.M., 3 P.M. – 11 P.M., and 11 P.M. – 7 A.M. Of the three, only the first one may experience heavy traffic in going to work as they join the regular 8 A.M. – 5 P.M. workers (with a noon to 1 P.M. lunch break). But regular workers almost always get the brunt of traffic jams.
While it’s true that traffic congestion is caused by simply too many vehicles on the road, oftentimes it may also be a result of tailgating. Many of us have this notion that to reach our destination faster, we have to get as close as possible to the car we’re following. It’s instigated by the thought that the capacity of an expressway, or any road for that matter, is measured by how many vehicles packed into it. So, if we place 120 cars on a certain stretch of road instead of 100, it would be more efficient.
Not exactly true. The capacity of a road is measured by the number of vehicles that pass through it in a certain period of time (“vehicles per hour”). That number is dependent to a great extent on the speed of the vehicles, which are assumed to be the same, especially on an expressway. That’s why I know there is rampant over-speeding in the Cebu-Cordova Expressway (CCLEX) because I always follow the 60 kph speed limit and get overtaken by a bunch of other cars. Expressways have design speeds which also indicate their capacity (in vehicles per hour).
Design speeds are attained by maintaining normal distances between cars. This also allows drivers to adjust speeds in case there are changes in the driving conditions of the cars up ahead. Some drivers have the mistaken notion that if they “tailgate” (get closer to the vehicle they’re following), it would allow for more vehicles on the road and thus increase its capacity. Wrong! Capacity is measured in “vehicles per hour” and is affected not just by the number but also by their speed and the latter is the defining measurement.
Different speeds require different “distances from the car you’re following” to keep your driving safe and to absorb slight speed changes. Tailgating prevents this and actually creates “phantom traffic jams” – traffic jams which suddenly appear when they shouldn’t have. That’s why sometimes we see jams in the middle of expressways when there’s none in the other parts. Those were “artificially” created, more often than not, by just one driver who tailgates and causes the chain reaction. That’s why this adage always works: “Keep distance!”