I think one of the reasons for Waze under-estimating route times has to do with it not properly correlating traffic speeds provided by its many users against the route selection. For instance, my route involves changing from a local highway that ends to an interstate where the left two lanes are the lanes you have to be in to get where I'm going. These lanes are often moving at around 5 MPH on average whereas the other side moves at around 60 MPH. Waze will indicate that the freeway is moving at an average of 40 MPH and will leave me on that road, rather than taking an easy, single-light traffic-free shorter route around the problem. I've never spent more than 5 minutes navigating the route-around, but I've had times where staying on has taken over 20 minutes (and 5 minutes would be fast most days). It rarely suggests the route-around (despite Waze having introduced it to me). It isn't intelligent enough to know that if I'm taking that exit, I'm the 5 MPH traffic, not the 60MPH traffic. It's either not taking into account that my route would result in slower traffic than average due to lane position, or it is and the other Wazers it's basing its estimates on are less conservative drivers than me -- I tend to get in the lane I need to be in early rather than flying around traffic and pushing my way in. It's got to be a really hard problem to solve, in general. Padding route estimates or estimating toward the worst-case scenario would probably be a good idea.

That said, Waze is the only app that has actually hooked me into using it on every trip, every time. The Waze app gives me speed limits and warns me when I am exceeding them by a pre-set amount[1]. It's also pot-hole season where I live and due to the wide user base of Waze and its hazard reporting, I get a warning (well, lately, hundreds of warnings) when there's one up ahead. By far the biggest benefit, though, is the police warning. I don't intentionally speed; I generally subscribe to the rule of "keep up with traffic" while keeping to the right-most lanes[2]. That said, keeping up with traffic has gotten me pulled over once (no ticket due to a decade of not having a ticket and my only exceeding the speed limit by barely 10 MPH).

In the last year, Waze has beaten me spotting the hidden police car every single time. I went on a 3-hour drive with a close friend who has one of those supposedly "covers everything" radar detectors and on that trip Waze spotted four more cops than his radar detector[3] did and had one partial false positive (he had moved ahead about a mile, so the app showed two cops instead of one) whereas his detector went off so many times in the city that he had to silence it. The avoidance of traffic fines and added insurance cost, alone, makes it worth it[4].

I'd say, for me, I started using the Waze app on the promise that it would get me around some of the unexpected traffic difficulties in my daily commute, but the reality is that after a few months, I know the areas involving my commute far better than Waze or Google. Both navigation apps have made me a slightly more intelligent driver. I'd often skip-off the freeway for surface streets when things got slow and was surprised when navigation apps wouldn't suggest to me to do that. It turns out that the time spent at traffic lights in traffic well exceed a slow freeway. It feels faster, sometimes, to exit the wall-to-wall 15 MPH slog, but you trade it for periods of 40 MPH traffic mixed with longer periods of just sitting idle.

But the bigger eye-opener that Waze seemed to do, which Google Maps didn't -- when there were lane closures, it'd have me enter the freeway at the first on-ramp before the lanes re-opened, rather than at some point after the lanes re-opened. And every time I ignored it, I ended up in some creative form of traffic hell. After thinking it through, I realized that the first on-ramp after traffic re-opens is often flooded with everyone else who's trying to avoid the construction. The last on-ramp just before the lanes re-open is not similarly flooded and yet traffic on the freeway is moving at about 60% of the speed-limit at that point and only getting faster as it reaches the re-opening. Since the last merge bottle-neck is that on-ramp and it's not clobbered with diversion traffic, it's a very good workaround.

[0] I don't own Apple products, so these are the two "big choices" on Android.

[1] I bumped it up from warning at the actual speed limit because driving the speed limit on some of the roads I travel is more likely to cause death-by-someone-elses-road-rage.

[2] Where I live, two-lane roads require drivers to remain in the right lane and use the left lane for passing and this rule is enforced ... just about never. Multi-lane roads are fair game with most remaining in the middle one or two lanes for the entire duration. I'm not even sure what the law is for these but if I were to judge based on how 90% of people drive, I'd say the law is to never be in the right lane, and that the left lane is for people traveling more than 20 MPH over the speed limit. We have no HOV lanes.

[3] I can't write that without thinking Radar Detector Detector Detector Detector https://rationalconspiracy.com/2016/06/02/radar-detector-det...

[4] "Well, you can avoid that by just not breaking the law." Except that traffic laws are among the few laws that are easily broken unintentionally.

The way Waze works is that it will do everything and anything it can to avoid a busy intersection or a congested street, without regard to whether or not going out of your way will take more time than just slogging through the intersection or the street. Waze will prefer a route that takes an hour but only takes streets that are empty over a route that takes half an hour but involves multiple busy intersections. Google optimizes its routes purely by time: whatever route will get you there the fastest is what it'll go with.

Waze also has a notorious tendency to encourage people to make left turns from the right lane and vice versa. It's illegal and dangerous. These instructions often take the format of "turn right on [six-lane arterial] and then immediately take the next left", even though it's physically impossible to get across the street in time.

Waze also cannot recognize the entrance to my townhouse complex as an entrance. It will always suggest cutting through a neighboring gated community to get to where I live. As a frequent Lyft rider, this means that I cannot ride with any driver who uses Waze if I'm going to or from my home.

I often have to call drivers who pick me up from my house and say "please confirm that you are not using Waze", and if they say they're using Waze, I will immediately cancel. If they're close enough though, I'll just monitor their route, and I'll immediately cancel if they take a route that only Waze will suggest (for example: the entrance to my complex and the neighboring gated community are on separate but perpendicular arterials; if they're driving on the arterial my entrance is on, but they drive past my entrance and then make a left turn on the other arterial, I'll know they're a Waze user, and I will cancel).

Sometimes, when I'm being picked up from work, I'll see a driver starting up Waze, and I'll say "please don't use Waze; it can't get to where I'm going". Sometimes, the driver will let me manually navigate them or on rare occasion even start up Google Maps, but I've also experienced a bunch of drivers who will throw angry temper tantrums because I asked them politely to not use Waze. One driver started screaming her head off at me while punching the steering wheel. I've had to get out of the car and call their trust & safety hotline a couple of times. I'm convinced that these drivers know that Waze will suggest routes that take more time than Google does, and that they are deliberately using Waze to run up the meter and make more money; as such, they get pissed off when a rider won't play along.

I like it for intra-town commutes where I know where I'm going already and just want to possibly try something new, but if I've never been to a place before or want the "works best 80% of the time" route, maps all the way.

YMMV.

Anecdote: A couple years ago, while driving into Toronto on the 401, we hit some traffic as always. Waze told me to get off at the next exit which I was fortunately right beside, so I assumed it was going to route me around the accident and back onto the highway after it cleared up. What it really did was take me up the off ramp, do a U-turn, and get back onto the on ramp to gain about 700m of distance from where I was before. It theoretically saved me 5 minutes of travel time, but it only really moved me a few dozen car lengths ahead.

Their wealth of real-time and historical data is certainly beneficial, but it also causes some truly bizarre navigation now and then.

Waze in particular is frustrating, as it aggressively routes you down side streets with the intent of saving you time, but following its route always seems to result in trying to turn left across two lanes of fast traffic (or pull straight through four lanes) with no traffic signal a minute or two later.

I do not want to save 1-3 minutes on a commute by cutting through unfamiliar residential areas where deaf kids play and homeowners give me dirty looks as I go over their oversized speed bumps.

I use Waze not so much as a super-optimal routing tool, but as an aggravation-avoidance tool. Traffic and speed-traps aggravate me, sure... but not nearly so much as trying to make a blind left from a stop sign at the top of a hill in my manual transmission.

Just yesterday I was in a somewhat unfamiliar area during crazy rainstorms near NYC... I used Waze since who knows what traffic looks like in those conditions.

In order to avoid 20-30 seconds of waiting at a traffic light it routed me to the next street over to make the left turn... which was on a curve with lots of parked cars and, in that weather, made it impossible to see if anyone was coming. If it hadn't been a one-way street I'd have considered turning around and going back to the light... but instead I used my best judgement and BARELY avoided getting nailed by another car.

Waze is great technology, but is still pretty naive about solving the problem I want solved. All the aggregated minutes of driving it has saved me over the last couple years would not have been worth it if yesterday's single poor routing decision had ended with me in the hospital/dead and/or my car totaled.

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and waze is far in the other direction, often telling people to get on and off highways repeatedly to save 30 seconds.

In fact, waze estimates it will save time, but in practice, it rarely does for me.

The routing of either is just a cost model for the same path finding engine. Maps seems to try to avoid various types of road transitions, assuming that it's traffic data isn't perfect and these things have some cost (IE traffic lights, etc, which are not accounted for except as average traffic speed) Waze seems to simply assume the apparently shortest fastest path will actually turn out that way.

Waze is often wrong, Maps rarely is. When Waze is wrong, it often takes only as long as Maps does or longer, (i've had Waze tell me to take routes it claimed were 5 minutes faster, that were 10 minutes longer). Maps is usually accurate, but it may leave something on the table.

I'd still rather have the second. Trying to pretend you have good data when you don't doesn't lead to good results. (IE garbage in, garbage out).

In NYC, it often makes absurd suggestions - I once got in an uber on 33rd and 2nd trying to get to penn station on 31st and 7th avenue. Far and away the most straightforward path is to head west on 31st street all the way to 7th avenue, but there's always a backup between 5th ave and 7th avenue - but that's still the fastest route. Waze directed the uber to head north on 3rd avenue to 39th street, head west, make a left on 5th avenue, then make a right on 35th, then make a left on 7th. It took twice as long, but we were always moving - it just wasn't taking into account how long it can take to make a turn on nyc streets.