It would be already great if Waze was able to take tunnel traffic conditions into account, based on average speed to go through it? I have a long tunnel in my daily commute and the lack of information on the traffic status inside the tunnel often results in long queues that could be avoided.
Average speed between two known positions based on GPS data should not be a major deal?

I thought Waze already used accelerometer data to accomplish this, but then everytime I enter a tunnel, it just pauses. This is easily corrected.

Please don't link it to data availability. What I notice is that especially in long tunnels Waze believes that I am somewhere in the nearest village outside the tunnel, I presume by taking my location from the data network?

4.0 is out (on iOS for a few months, apparently released for Android today however no update available on my phone), still no "tunnel mode"? This pretty important navigation feature was first requested back in 2010... I'm starting to loose my faith in Waze, having missed several exits in Stockholm's tunnels (first time there driving my own car) a few weeks back.
Please, Waze, replace your "tunnel panic mode" with a simple, decent "tunnel mode" where the app just stays on route/road with last known speed until gps signals are available again. How hard can it be? (I really don't know! :-) )

In London, there is a tunnel which forks underground. No satnav, WAZE included can get a GPS signal.

It would be useful if Waze could give directions ahead of time when you approach an area or stretch of raod (eg a tunnel) where it knows (from prior users' experience) that it is certain or likely to lose signal.

Additionally, or alternatively, there could be an user-selected option where, when signal is lost, Waze either a) considers the car to have stopped, or b) considers that the car is continuing at the same average speed as just before signal was lost.

This idea was exhibited in Brazil in the first meeting of wazers
This was my presentation http://www.slideshare.net/alvtej/waze-rio
Go to Slide 19.

Kalman filtering!

Dead reaching could be used when in tunnels.
https://en.wikipedia.org/wiki/Dead_reckoning

There is one very big issue with this. How does the app track your progress in a tunnel?? The app, like all navigation apps, use the signals from GPS satellites to work out where you are. These signals are not able to reach your phone/tablet whilst you are in a tunnel. Try listening to a radio station in a tunnel and see. How about phoning someone? "opps! sorry, entering a tunnel, losing the sig........"!

Upon entering tunnels or other areas where navigation is unavailable, add an option that automatically forwards your vehicle icon to the next "decision point" (ie. turns, traffic lights, road forks, etc...), that way the driver will know which direction to keep heading. Having a "next" option would also allow the driver to forward the icon to the next decision point once he/she has passed that point. It is very common to encounter forks in the road in tunnels or come out of a tunnel and pass my turn while Waze is re-connecting or unavailable.

I've been stuck on my way to Paris on the A14 tunnel for nearly 1h30. It took me 2h30 while waze suggested 1h for my total trip !
This was the worst suggestion ever.
I don't understand why I didn't get any update from the app since I was able to get mobile network without any problem. A fix is needed urgently for this major issue IMO. I can"t imagine that Waze doesn't see when we get in and when we get out the tunnel.

When I am waiting under a road light between two 10 story building then the GPS signal strength gets weaken and Waze thinks "I have made a U-turn, than back, then turned left, no, right".

Waze should use the built in compass, before such event deduction to be sure. Or simply know that it is impossible to "make a U-turn, than left, then right" in 1 second.

Having read all of your comments you, sir, are obviously EXTREMELY GENIUS.

I wouldn't be surprised if google has hired you.

3 years later CSR has GNSS chipsets with many of these features I hope will be available on SoC in upcoming android flagship phones.

MediaTek also has developed some great gnss chisets with similar features while csr sat on their collective Sirf hands.

I do hope to see dead reckoning implemented in software for those disinterested in flagship phones or unfavorable conditions

Yes, Waze reads the suggestions. Check the Wishlist here : https://wiki.waze.com/wiki/Wishlist

Tunnels are entry #14

Navigon / Garmin has a tunnel navigation mode and Waze really needs one too. Especially where you have tunnels - like where I am in Stockholm - as here, we have multiple splits and exits inside tunnels.

Nicolas Bougues has a great suggestion. Waze's inability to extrapolate tunnel conditions leads to bad routing recommendations relating to them (e.g. every time I go through the Boston Central Artery Tunnel my estimated arrival time improves by five minutes as soon as I exit. Also, it's not uncommon to get poor route recommendations because Waze believes that there's significant congestion - frequently routes involve getting off the highway, taking local roads and then getting back on OR driving to a distant highway entrance for no particular reason).

When I use TomTom on my iPhone it posts estimated location

Someone mentioned using FM as a dead reckoning method. I think that would be awesome!

"So waze's only option would be to clamp the car to the street it is driving on and predict the position with the latest speed."

I totally agree. The algorithm I would use is if road elevation < ground level && gps lost then propagate the estimated position along the Waze route at the last known speed. When road elevation returns to ground level or above then freeze the position until gps returns.

Seems such a simple implementation to me for what would be a huge benefit. If there is an exit half along the tunnel you get no guidance. What use is that?