Parking Tour Generator September 2018

Parking Tour Generator Explores a sequence of roads like a parking expert would Guidance tells you when to park, or not park Parking Tour in vicinity of destination is constrained by max preferred walking time Link 1 is the first within max walking time (here it is 10 mins) Red means “don’t park yet” Black means “park if there is a space”. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Tours differ from Routes in important ways There is no specific end point. The Tour does not know where available parking spaces are, it just knows parking probabilities. The same road may be visited multiple times if that is an easy way to explore the area. (No loops in Routes). A series of roads may be visited multiple times if enough time has elapsed for spaces to be vacated. The tour may recommend NOT parking in some places if it knows better opportunities are coming. There may also be areas bad for parking where the final walk is difficult, or parking time or cost restrictions apply.

Parking Tour Generator Cost Function The Parking Tour Generator is very different from a Router There is still a Cost Function though to model the trade-offs a driver makes Weighting includes: Driving Time Walking Time Parking Charge Parking Time Restictions Ease of Driving, e.g. left or right turns Ease of Walking, e.g. major road crossings

Parking Tour Generator Probabilistic Cost Function We do not know where parking spaces are available, only the probabilities of finding a space To find a Tour we do not minimise components such as Walking Distance, but rather Expected Walking Distance This approach is very flexible, e.g.: Less walking if it is raining, with a longer tour Faster parking if late, perhaps in a more expensive space If there is plenty of parking our Tour will head straight for destination area. When parking is rare the Tour will cover roads further from the destination, but in a pattern the covers the maximum area in the shortest time.

Parking Tour Generator Data Requirements Historical Parking Data The probabilility of parking on a given stretch of road at different times of the day and week Churn Interval How soon it might be worth re-visiting a stretch of road The algorithm gives useful results if only partial data or no data is know A default Churn Interval of a few minutes works well A default parking probability on appropriate roads generates useful Tours

Parking Tour Generator Example Tours Plentiful Parking A good Tour will search near the destination. The Tour will advise against parking until the destination is within easy walking distance. Here, a uniform parking probability of 0.1/100m advises parking from link 12 onwards. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Parking is rare Advice to park at an earlier stage. This will reduce the expected Tour time. A uniform parking probability of 0.03/100m advises parking from link 6 onwards. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours High Churn Rate It is worth revisiting a road if enough time has elapsed for the parking probability to have recovered. Here, the Tour driving time has been increased to 600s, and more loops are generated. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Low Churn Rate It is now best to drive a larger circuit before revisiting roads. Here, links [17,44] and links [12,46] are revisited after 5 mins. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Dislike Walking We expect to see more time driving, but closer to the destination. Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Emergent Behaviour The tour explores all the aisles sensibly, exploring the end ones first as they are closest to the walking paths (except for [57, 58] as that is one-way) Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Turn Penalties The surprising behaviour when we applied an artificially high weighting was a tour that visited all the aisles while never turning right after link 24 (in the UK) Map tiles and road data © OpenStreetMap contributors

Parking Tour Generator Example Tours Extreme Tours How to optimally find a space in a Park and Ride Map tiles and road data © OpenStreetMap contributors