| Issue Id | Issue | Implications | Recommendation |
|---|---|---|---|
| 1 | Turn restrictions model time periods implicitly as AM,PM,and AMPM | 1. Exact interval on turn restriction is lost in source conversion from interval to AM/PM designation. Both 1600-1730 and 1600-1800 become PM 2. Can’t represent all-day restrictions such as 0600-1800 which is an example from a No Left Turn restriction from Violet to Interurban |
Change from implicit to explicit (24hr) time intervals |
| 2 | Turn restrictions specify turn directions which may be ambiguous | 1. There may be two left turns from a given road segment end which makes No Left Turn ambiguous 2. There may be no straight through which makes No Straight Through ambiguous |
Adopt Edge-Node-Edge model |
| 3 | Multiple intersections can’t be associated with a single traffic control | Multiple intersection traversal costs are incurred (e.g., 3 times instead of once in the case of a left-turn at a divided road traffic light | Add the concept of a controlled intersection and a one:many relationship between a controlled intersection and an intersection |
| 4 | One-ways not consistently used for turn lanes and ramps | Without a one-way, extra turn-restrictions are required | Make data consistent |
| 5 | Truck turn restrictions not supported | Needed for truck routing | Add support for explicit turn restrictions based on truck dimensions. Consider generating tight-turn warnings based on truck dimensions and turn-angle in Routable BC Maker. |
| 6 | Tight maneuvers (S-curves) not supported. | Needed for truck routing | Add hasTightManeuvers property to road segment |
| 7 | Overweight corridors not supported | A road segment can only belong to one designated truck route but overweight corridors run on designated routes. | ? |
| 8 | Traffic congestion on road segments not supported | Needed for support of historic and real-time traffic congestion | Since this data will likely not be crowd-sourced in the foreseeable future, provide traffic congestion through another web service (e.g., WFS). |
| 9 | Seasonal load restrictions not supported | 1. Seasonal load restrictions may involve axle weight load factor, noOverweight and noOverSize flags, geometric extent, and an effective time-period 2. Each district or region may have its own maximum GVW |
Don’t extend data model. This data can’t be crowd-sourced so should be made available through another web service (e.g., OGC WFS). |
| 10 | Grade restrictions not supported (e.g., 9% grade) | Can’t avoid steep grades in routes for big rigs | ? |
| 11 | No way to specify a road is closed | Need to specify a road is closed in both directions or a given direction | ? |
| 12 | Road ramp doesn’t have an associated slope property | Insufficient information to determine if a truck can safely turn onto a given road ramp from a sharp angle (e.g., less than seventy degrees) | Add slope property to road ramps |
| 13 | Only one of four truck weights is represented | Truck permitting requires four: GVW, Single Axle, Tandem Axle, Tridem Axle. | Leave single weight value for now. Full dimension restrictions will come from a separate, MOTI restriction data service that ties road-restricting features to ITN road segments. |
| 14 | Only one height restriction represented | Height restrictions vary by lane and travel direction. | Leave single height value to represent minimum max height across all lanes and both directions. Detailed height restrictions will come from a separate, MOTI restriction data service that ties road-restricting features to ITN road segments. |
| 15 | No time-dependent max speed property | Can’t represent school zone speed limits which are only in force during school hours | ? |
| 16 | NO implicit flag in turn restrictions | Can’t tell if a given turn-restriction should have a sign on the ground for QA | Add implicit flag to turn restrictions |
| 17 | Some access restrictions are represented as road names instead of access restriction codes | Best routes will include road that a given vehicle type is not allowed on | Add appropriate access restrictions |
| 18 | Turn-restrictions need a vehicle type property | Can’t specify a truck-only turn restriction | add vehicle-type:String property with possible values of truck and any |
| 19 | Many yield lanes are missing | Best route duration will be a bit higher because yield lanes have lower turn cost than stop lanes | Add yield lanes |
| 20 | All 22,000 intersections on the backbone and ribs of the highway and Greater Vancouver road networks need their turn-restrictions validated and corrected if necessary | Best routes will contain illegal turns | Validate and fix turn-restrictions |
| 21 | Many divided road intersections are missing connector segments | Missing segments will prevent the router from including valid turns that could make the best route faster | Add missing connector segments |