Mapping a parking lot road serves three purposes:
- it allows Waze to provide door-to-door directions within the lot;
- it allows the Waze to recognize that the client is off the main road, avoiding erroneous traffic reports.
- using the special type prevents Waze from routing traffic through the parking lot.
Parking lot segments are not related to the Parking Lot Place type, though they are sometimes used together.
The Parking Lot Road type exists to allow the mapping of parking lots, while discouraging the routing server from using them for through navigation. Waze applies a transition penalty for leaving a Parking Lot Road segment to enter another road type. This penalty decreases the chance that Waze will route through a parking lot as a shortcut but allows better navigation in and out of a parking lot. It is advised not to mix road types within a parking lot to avoid triggering the transition penalty unnecessarily.
When mapping a large parking lot (e.g., at a shopping center) consider mapping only the following:
- Main entrances from the roads outside the parking lot
- Lanes that run along storefronts
- Lanes at the edge of the lot which run alongside public roads (prevents Wazers in the parking area from "snapping" to the public road, and then sending incorrect speed information it)
- Primary travel lanes that serve to get people from one area of the lot to another
Remember, the goals here are usability and simplicity. When in doubt, imagine yourself in a car in the lot at various points, and ask yourself what the most efficient way would be to get to a store at the other end of the lot, or to exit the lot and get back on a main road, with as few convolutions as possible. The lanes that are used the most in this thought experiment should be mapped, with the rest being omitted. You can turn on the GPS points layer (Shortcut key Shift-G) to see where traffic is concentrated to get a sense of what needs mapping.
In particular, do not map every single lane, and especially not every single parking space (it has been done!). This serves no purpose but to clutter the map, confuse directions, and put an unnecessary burden on both the client and server hardware. Remember usability and simplicity are #1. Your editing time and expertise can be better used elsewhere in the map.
Small Parking Lots
Parking lots that serve a small number of businesses should be minimal: enough to give the driver correct directions into and out of the lot, and navigate to a particular business. Very small lots with one entrance and one exit could even be represented by a single segment running through the parking area (either a diagonal across the lot if it connects to roads on each side, or a single, flattened curve for strip mall-style lots with entrances and exit along the same road).
To permit a route to be given to exit a small parking lot from the same point the parking lot was entered, u-turns may be enabled at the ends of the parking lot road. This is particularly relevant where a single parking lot segment connects two different street segments such as is common for many corner gas stations.
Because these lots can be narrow and congested, with one-way sections, the simplest way to represent them may be as just a one-way drive-through loop. Caveat: because both ends of a segment cannot connect to the same junction, if the lot has only one entrance/exit, it is necessary to build the loop using three segments.
Two parking lots connected to the same street
Bad routing can occur when two parking lots connect to the same street. This can happen, for example, where two lots face each other. If you connect both parking lots to the street using the same junction as the connection point for both, Waze will treat them as one parking lot.
If there are no turn restrictions preventing routing across the street, Waze may route the driver through one parking lot to reach a destination in the other parking lot. Waze is designed to avoid such routes, but in this configuration, Waze does not apply the expected penalty - because crossing through the junction from one parking lot segment to the other is not considered a transition, even though there is also a street running through the junction. This may be most easily understood by looking at the example image below.
If it is not legal to cross from one lot to the other, turn restrictions will prevent any sort of routing between the lots. However, if it is possible to route from one lot to the other, then a different method is required to prevent routing through one lot to reach the other.
To be sure that Waze will apply the transition penalty when routing through one parking lot from another, the two parking lots must be isolated from the each other such that passing from one to the other requires driving over a standard road segment (not a parking lot road or private road). You should map a very short "stub" segment (5m/17ft) of a standard road segment. This segment will run from the junction to the entry/exit segment of one of the lots. With this configuration, exiting the parking lot will have a consistent penalty, whether the route exits the first parking lot to the street or the route leads to another parking lot at the same junction.
Parking lots do not have to be across the street from each other. In a strip mall, if the exit segment of one business is joined to the entrance segment of the next business, the same problem can occur.
For example, in the configuration shown below if routing from the west parking lot, there is no transition penalty to route through the gas station parking lot on the east side of the street if routing east on Riva Rd. Conversely, if routing to the west parking lot from Riva Rd. there is no transition penalty to use the gas station.
This potential problem arises when two parking lots on opposite sides of a street connect at the same junction node on the street.
If this configuration causes routing problems it can be solved by changing the road type of one (or both) of the parking lot roads that intersect with the street.
A five meter or longer stub of a different road type will accomplish the same result.
If the street is a divided highway, then the road type of the crossover segment may be changed (this may also allow U-turns at the crossover segment).
Parking lot places and gas stations
A parking lot road (PLR) is used for the purposes described above. A parking lot place is used to help drivers locate a destination to route to. In some cases, for large parking lots, it may also be used for visual identification on the map.
Using one does not require using the other. Our policy, with a number of exceptions, is that most parking lots are not mapped as parking lot places. Unless the parking lot you are mapping falls into one of those exceptions, you may map its roadways as PLRs but not create a parking lot place. If you do create a parking lot place, it may be a place point or an area place (using the rules for Places). If it is a point place, it may or may not have any PLRs mapped for it, depending on whether Waze should provide drivers with useful directions within the lot. If it is an area place, you will probably map PLRs within it.
Gas stations are always mapped, and are always an area place. You should map PLRs through them, using the rules described above for small parking lots.