Nowadays the traffic jam is a big problem in our city, the mobility is getting worse every day. Every day is more difficult go from one side to another, we have to wait a lot of time because of the congestion.  
The growth of our city is increasing every day and at the same time the number of motorcycles and cars. Nowadays is very easy buy one vehicle and a big part of the families have at least two vehicles in every home. In Medellin for every three people there are a car. Colombia have today 6,8 million of cars and motorcycles and the number will continue increasing. 
On the other hand, a study argues that the fully loaded tractor-trailer has a heavy of 80.000 pounds, and a particular car has a heavy of 4.000 pounds, I mean, it's 20 times difference in weight, but the wear and tear caused by the truck is exponentially greater. Furthermore, Road traffic accidents is the main cause of death. The tailgating occurs daily. Many fatal car accidents have occurred when a motorist dangerously tailgated another driver at high speeds. 
Finally, the last problem that was consider, is about the schedule that the person have to work, because this coincides in many cases, and in consequence the public transport do not have the capacity to keep the order in the mobility in the city. The principal effect of this problem is the need of the public transport,( like the bus), to stop to collecting each passenger and causing a reduced mobility that is a main cause of the traffic jam.