The expected waiting time in system for typical truck is 2 hours.
Step-by-step explanation:
Data Given are as follows.
Truck arrival rate is given by,   α  = 36 / day
Truck operation departure rate is given,   β= 48 / day
A constructed queuing model is such that so that queue lengths and waiting time can be predicted.
In queuing theory, we have to achieve economic balance between number of customers arriving into system and that of leaving the system whether referring to people or things, in correlating such variables as how customers arrive, how service meets their requirements, average service time and extent of variations, and idle time. 
This problem is solved by using concept of Single Channel Arrival with exponential service infinite populate model.
Waiting time in system is given by,

         where  is waiting time in system
 is waiting time in system
                     is arrival rate described Poission distribution
 is arrival rate described Poission distribution
                     is service rate described by Exponential distribution
 is service rate described by Exponential distribution


 
 
 ...it is due to 1 day = 24 hours
        ...it is due to 1 day = 24 hours

Therefore, time required for waiting in system is 2 hours.