For safe, smooth and fast moving, the road space is divided into lanes.

On Four lane roads having two lanes for each direction of traffic, use the right lane for the purpose of overtaking or for making a right turn or U turn.

On 6 lane roads having 3 lanes for each direction of traffic, left lane meant for normal driving and left turning vehicles. Middle lane is for fast moving straight vehicles. Right lane is meant for over taking or right turning or for making U turn.

FOUR LANE TRAFFIC SYSTEM

The "Four Lane Traffic System" has been implemented at the stretch of Anna Salai from Anna Statue to Whites Road Junction from 18.05.1992 onwards (vide GO.Ms. No.775) and over these years this system has been working well. Subsequently, consequent to the inauguration of "Chennai Moffussil Bus Terminus" (CMBT) at Koyambedu, it is noticed that the piling up of traffic on the third lane meant for the Buses/Heavy Vehicles, is comparatively reduced than the other two lanes meant for two wheelers/auto rickshaws and cars/ vans respectively.

In this connection a study has been conducted and according to the study about 3484 Medium passenger Vehicles/Medium Goods vehicles etc, are also using second lane (meant for cars) resulting on piling up of traffic on that particular lane.