Road types aren't just for show, they make a difference in the routing server. The server doesn't have the time or resources to look at every single street between where you are and your destination, so it uses road types for guidance in selecting the best route for you. Road types aren't everything — of course, Waze uses actual and historical traffic speed data to select the fastest route for you at a given time — but they are important. They show Waze which roads to check when looking at that traffic speed data. So setting the type too low can mean Waze doesn't consider a road which may actually get you there faster.
Freeways are a fact of life. While freeways are by design often the fastest way from A to B, we all know this isn't the case every time. Sometimes a freeway just isn't convenient. Other times, freeways are clogged with traffic, while surface streets flow rather freely. Sometimes both situations are faced — without traffic, maybe the freeway adds 5 miles to your route, but it's faster anyway; today, though, the freeway is backed up and taking the 5-mile-shorter route will save you time.
Freeways are the highest type of road in Waze, often assumed by the routing server to be the best alternative. Sure, they often are, but that isn't always the case. For Waze to consider other roads as viable alternatives, there need to be other relatively high type roads — Major and Minor Highways — in the area for Waze to consider, or else you might just end up on the freeway in that traffic jam anyway.
Further, road types are increasingly important for longer routes. Yes, Waze is designed as a commuter application, but it'll provide routes up to a thousand miles. I've used Waze on dozens of thousand-mile-plus road trips, and it's performed admirably. And some people just have long commutes. Well, as we know, many lower-type roads are not considered at all by the routing server for routes longer than a certain length. The longer the route, the higher the road type has to be. For travel within a state, Minor Highways could be enough. For travel through the States, you want at least a Major Highway.
The current rules for setting road types in the United States are based on the physical characteristics of the road and are somewhat nebulous. The vagueness of the standards leads to inconsistent application, with editors in different parts of the country using different criteria for choosing road types. This leads to an inconsistent user experience across the country, even within states. It's even led to disputes, with editors who disagree on what type best suits a particular road, switching the type of a road back and forth.
Luckily, the federal government has a solution for us. The Federal Highway Administration (FHWA) has come up with a set of standards by which every road in the country is judged: functional classification (very short explanation here). The functional classification of a road is determined both by the physical characteristics of a road and by the Average Annual Daily Traffic (AADT) — the number of cars that, on average, drive on a particular road each day. Each road is therefore placed in one of the functional classes; each functional class describes a particular usage scenario for the roads in it. The functional classification criteria are passed on to the several States, and each state's department of transportation in turn uses the criteria and their own research to gather information, to classify roads, and to publish maps showing the functional class of every road in the state.
The federal government further provides guidance to us by designating roads as parts of the Interstate Highway System and the United States Numbered Highways system. The roads themselves are built and maintained by the states; but in selecting the routes, the federal government identifies a network of important long-distance travel routes throughout the country. Finally, the government of each State (and D.C., and some territories) designates roads as parts of its respective state highway system; these routes are selected for their importance in travel within a particular state.
Luckily for us, functional classification and the various highway systems comport quite well with Waze's set of road types.
|Functional class / highway system||Waze road type|
FC: Other Freeways and Expressways (some)
|FC: Other Freeways and Expressways (others)|
FC: Other Principal Arterials
HS: U.S. Highways
|FC: Other Arterials|
HS: State Highways
|FC: Major Collectors|
FC: Minor Collectors
HS: County Routes
This system has already been put into place for testing in various metropolitan areas, including New Orleans and Detroit. Besides the clear improvement in definitiveness of road type selection, many other editors and I have noticed a marked difference in the performance of the routing server and in other aspects of Waze since implementing the systems.
- Waze is more likely to select the best possible route at the start, without you having to ask for alternatives
- Waze is more likely to select alternative routes in the case of clogged freeways
- The map display becomes more useful, showing the most important roads with thicker lines and at higher zoom levels — and, bonus, allowing you to see at a glance where the "downtown" area of a city is (examples: New Orleans; Detroit)
- As said above, as a well-defined system, it does not allow for disputes and may make frivolous edits easier to discover
- Temporary: Currently, road type is the primary factor used to judge traffic jam highlighting. That said, I've been using Waze daily in New Orleans for months with this system in place and have not seen any instances of erroneous jam highlighting. Also, staff has announced that road type is soon to be replaced as the principal jam-highlight criterion with something else based on the actual jam-free speed of the road.
Here is the proposed page: https://wiki.waze.com/wiki/Road_types/USA/Revision
Note: As you'll see, this doesn't cover non-drivable and non-public road types (parking lot roads, private roads, walking trails, etc.). While much of that section of the article does need revision, it should be carried out in another thread.