New public-health studies and laboratory experiments suggest that, at every stage of life, traffic fumes exact a measurable toll on mental capacity, intelligence and emotional stability.

The NHTSA (National Highway Traffic Sefety Administration) has suggested the 'TTR' method as one means of regulating the roll stability properties of light trucks and utility vehicles.

Using the theory for differential equation stability, this paper investigates a struggle relationship between two traffic modes in city traffic volume , and shows they suit Gause' s model.