There is a zone known as the dilemma zone located on each arm of a signalized intersection. In the dilemma zone, there is a decision to go through the intersection at the risk or a decision to stop suddenly. The longer the dilemma zone, the higher the risk that the driver will pass through the intersection. Therefore, the purpose of this study is to present a comparison of visual observation data between car and motorcycle regarding the length of dilemma zone for 3 seconds yellow interval at the 3-arm signalized intersection. The length of dilemma zone for car is longer than motorcycle in peak-hour (by about 100%) and this can be found that the acceleration/ deceleration time for cars are slower than motorcycles. Other result shows that the length of dilemma zone for cars has significant different in off-peak hours and peak hours.