Many things go into how long it will take you to run your race, including the number of racers entered, number of lanes on the track, which scheduling method is being used, and race crew organization. Since you have little control over the number of racers entered, we will cover the other issues that you do have control over.
Race Crew Organization
How efficient your race crew is has a tremendous effect over how long it will take to run your race. Here are some things that we suggest:
Some scheduling methods are faster to run than others. Ideally, you do not want to wait for cars running in back-to-back heats, as this makes you wait for cars to return from the finish line before starting the next heat. Perfect-N Type, Phase Shifted Lane Rotation and Modified Lane Rotation schedules are better at reducing the back-to-back issue. Though, having a small number of cars in a race group and how many lanes your track has can also affect the back-to-back issue, regardless of the chosen scheduling method. Also, you may want to consider using the software's Master Scheduling feature, which alternates through heats from your different race groups. This is another way to prevent cars in back-to-back heats.
Number of Track Lanes
Many organizations when they go to build or buy a track feel that more lanes is better. Well, that isn't necessarily the case. It takes more time to run each heat as you add track lanes. There are more cars to load to the track, to retrieve from the finish line and to put back in their assigned "parking spots". If you have a track with more than 4 lanes, you may want to consider reducing the number of lanes that you will actually use for your race.