Answer:

At t=0, the cyclist is moving at v1 = 15 m/s.

At t=0 the race car is moving at v2 = 0 m/s (at stop light).

At t=3.0 s, the cyclist is moving at v3 = 15 m/s ("constant velocity").

At t=3.0 s, the race car is moving at v2 + a2*(3.0),

so if the car accelerates at 5 m/s2, at the end of 3.0 s, it is moving at 15 m/s, equal to the cyclist.

If the race car accelerates at more than 5 m/s2, it will be moving faster than the cyclist at t=3 s; if the race car accelerates at less than 5 m/s2, it will be slower than the cyclist at t=3 s (but this won't be the case much longer).