Objective Question & Answer

Flexible Progressive System (Most Efficient): In this computerized system, the cycle length,

cycle splits, and time schedule at each intersection can be automatically varied based on

real-time traffic volume. It is highly adaptive, reduces overall delay, and provides the

maximum traffic handling capacity.

Simultaneous System: All signals along a route show the same indication (e.g., all green or all

(red) at the same time. This forces frequent stops and is generally inefficient.

Alternate System: Successive signals along a route show opposite colors simultaneously. It

works adequately only if intersections are uniformly spaced and traffic speeds remain

completely constant.

Simple Progressive System: Signals are scheduled to display green phases at a fixed,

predetermined time sequence along the road to maintain a constant vehicle speed, but it

lacks the real-time flexibility to adjust to changing peak hours.