Chicanes on the course can add a great deal to the event;

• Extra challenge for the drivers
• Extra excitement for the competitors 
• Add interest to an otherwise fairly straight course
• Force drivers to slow down before any course hazards

If penalties are to be imposed for obstructions hit, it is worth considering an objective measure of whether or not to apply the penalty. For example, if you use traffic cones to make a slalom, a tennis ball on the top of it will indicate if it has been hit.