You can get the representative sample for the whole population by asking the users randomly at origin and destination places.

However, it depends on how you do maintain the randomness in drawing sample.

Maintenance of more the degree of randomness yields more degree of representation of the population by the sample.

You can use a systematic sampling method based on the movement of traffic in specific areas, but beware of periodicity

You can use Stratified Random Sampling treating the the destination places as Strata. Draw sample of users at random from each stratum and then combine the random samples drawn from the strata to obtain the required stratified random sample for the study.

Dear Dhritikesh Chakrabarty , let us discus on the selected route which has one destination and origin place.

Again for Isaac Oshungade , How systematic sampling will maintain randomness as long as movement of traffic is periodic dependent in either rush hour choice or free hour choice?