This paper focuses on starting-delay when vehicle starts accelerating when signal phase turns to green at a signalized intersection. How the reduction of starting-delay affects traffic throughout and emission was discussed. The authors proposed three different approaches to reduce the starting-delay such as (a) increasing sensitivity factor "a" of car-following model, (b) decreasing reaction time "T" and (c) both increasing "a" and decreasing "T". Traffic simulation was done for each starting-delay measure with different heavy vehicle penetration ; 0, 10 and 20%. Here, in this paper, traffic throughout was defined as the clearance time duration when the total traffic demand completely left the intersection. Also, emission is represented by CO_2 only. Numerical analysis significantly showed that reduction of reaction time effectively decreased CO_2 clearance time.