max_trip_duration should be limited by cutoffs

[rafapereirabr]

In the accessibility function, max_trip_duration is set to 120 (minutes) by default. So R5 will search routes to really further away places. However, I understand that when a user sets cutoffs = 30​, the max_trip_duration should automatically be affected. It seems like this is not happening.

obs. having a max_trip_duration longer than cutoffs does NOT affect accessibility estimates, but it does affect computation time.

[rafapereirabr]

The solution would be to add this line of code:

 # cap trip duration with cutoffs
  if(!is.null(cutoffs)){
    max_trip_duration <- ifelse(max_trip_duration > max(cutoffs), max(cutoffs), max_trip_duration)
  
  if(max_trip_duration < max(cutoffs)){stop("'max_trip_duration' cannot be shorter than 'max(cutoffs)'")}
  }

before the accessibility() function runs:

  max_walk_time <- assign_max_street_time(
    max_walk_time,
    walk_speed,
    max_trip_duration,
    "walk"
  )
  max_bike_time <- assign_max_street_time(
    max_bike_time,
    bike_speed,
    max_trip_duration,
    "bike"
  )
  max_car_time <- assign_max_street_time(
    max_car_time,
    8, # 8 km/h, R5's default.
    max_trip_duration,
    "car"
  )
  max_trip_duration <- assign_max_trip_duration(
    max_trip_duration,
    mode_list,
    max_walk_time,
    max_bike_time
  )