Can somebody please help me with this. I cannot figure out how to make this work? I keep getting the following error: Error, (in treach) cannot determine if this expression is true or false: 17

Hi i'm working on a simulation and have got stuck. The simulation is for cyclists cycling on a circular track. There is a section of track which is treacherous and all cyclists who pass through this point must observe a certain maximum speed until they have cleared this area and can continue round the track as fast as they can although keeping a safe distance behind the cyclist in front. It is assumed for simplicity that cyclists cannot overtake each other. These are my workings so far: >bicycle := (pl,sl,len) -> (pl+sl) mod len: > >vel:= proc(pl,len,vmax) > local n;