How to apply an accidental vehicle in my model in accordance with CS454? Can we perform Transverse Lane Optimization for Permit Truck? 

Answer : We can create the accidental vehicle in Midas using the "Permit Truck" option under "User Defined Vehicle". 

D1, D2, Dn.... are the distance from the centre line of vehicle. As the vehicle is symmetric, thus we need to apply the vehicle definition as shown below. Modify each axle by defining only one side of the vehicle with D1 value as 0.9m (which is half of the axle width) and checking the symmetric vehicle option on.

Q2) 
Answer: Transverse lane optimization cannot be performed for permit vehicle.