Nuvi Avoidance: Car Pool Lanes

There are some places/highways that have "major" carpool lanes ... entire, separate highway sections w/ their own on and off ramps - it is these that I think that nuvi will/will not avoid based on your avoidance selections.

I have never experienced the nuvi do anything when one lane of a 4 or 5 lane highway is painted as HOV. They are not accurate enough to know the exact lane you are in.

Here in Washington D.C., we have an Interstate, I-66, that becomes completely HOV during certain times of the day.

I have that option set in my Nuvi, and during the carpool only times, the unit will not route me on the road.
If the carpool only time has passed, it will route me there.

We also have an exit on I-66 that is carpool only at all times (it is closed when it is not in use). The Nuvi will not take me on that ramp at any time.

Thanks for both responses...and within 12 minutes from the time I asked my question!

I found your answers made such sense that I immediately tested them out.

We have a bridge in the Seattle area that is totally dedicated to car pool lanes (known as Express lanes, that parallel the I-90 Bridge).

I was amazed that my plotted route (with Car Pool Lanes enabled) Westbound into Seattle was correctly displayed, as specifically using the I-90 Express Lanes (labeled as such!), and correctly displayed the bridge for them, which is directly adjacent NORTH of the main I-90 bridge. This route also SEEMINGLY reflected the fact that these lanes are Westbound during the AM. This was perfect!

However, when I "disabled" the Car Pool Lanes, the 855 STILL routed me Westbound via the same Express Lanes bridge. I also turned off and removed the battery to ensure a total reset of my Avoidances, but got the same result. Not good at all, since it ignored my "Avoid" selection!

Further, when I did a "simulated" route Eastbound FROM Seattle (with carpool lanes back "ON"), the Express Lanes bridge was incorrectly displayed to the SOUTH of the main I-90 bridge, and MUCH WORSE, it routed me Eastbound during this same AM period...when those lanes are exclusively restricted to Westbound traffic: BAD Move! It is possible that the Nuvi in Simulation Mode does not plot routes based on time of day...

I would appreciate if anyone could speculate on why my Nuvi has experienced these anomalies, especially the fact that my 2nd test (with lanes marked as "Avoid") still resulted in the carpool lanes being selected.

Regardless, I sincerely appreciate the fact that you guys replied with totally logical explanations, based on your local experiences. You have at least got me started on a solution to my question: I will try to work out some answers to the new "mysteries" on my own.

You have to make sure you do this simulation during the times that the carpool lanes are in effect. Even when simulating. Also, you when simulating, be sure that the direction you are traveling, has carpool lanes available during that time.

I understand what you are saying about the dedicated lanes, but the Garmin may only know normal carpool lane times.

Only speculating here, but it seems plausible that being in simulation mode might not consider time of day. Simulation mode turns off the sat. comm. which may, in turn, cause the nuvi to ignore or not be able to calculate based on time of day.

Run your same test with sat. reception and skip thru the turn-by-turns to view the results ... of course, it should vary based on when you do this.

It still knows what time it is. The internal clock is only dependent on the satellites for time updates.

I know that the clock still works, but does it use this time in it's calculations when their is no sat. comm.??

Yes, it does. Simulate a route, then look at the map screen. It will show your ETA in real time. Again, the internal clock is used for calculations, the time from the satellite only updates the internal clock when it varies.

The time itself transmitted from the satellite is not used for route calculations, only for position calculations.

Phranc - I'm not arguing with you, as I do not know the answer. As stated previously, I was just speculating.

While I know that the nuvi displays the time and ETA during simulation mode and that the clock still works during times of no sat. comm., how does this prove that this is the data used when calculating time-of-day dependent routes. It would be somewhat logical that all necessary data be mined/sourced from one place - the sats. ... no??

As there are so few routing instances that would be effected by the time of day - just HOV lanes that I can think of, I have never considered this before. What leads you to believe that it is the internal clock that is used? I don't think that just because the clock works in sim. mode that one can conclude that the clock is used for route calculations in 'normal' operation ... sim. mode is just that, a simulation. (again, I don't know and I am not claiming you are wrong ... just asking how/if you know)

If you were only guessing or assuming due to the clock working, the proof would be for someone to run a few simulations, at different times of the day, of an area like donbadabon references to see the results - an area where time-of-day dependent routing has proven to work. That would allow one to draw a conclusion as to whether nuvifan is seeing a result due to being in simulation mode or due to mapping issues in his area.

Maybe I'll have time to try this at some point ....

There was a news article posted a couple of weeks ago that spoke to this very subject. Navteq stated their map data had information about car pool lanes and reversible lanes when it was provided to the GPS companies. It was the company's choice to use or ignore the data. The road used in the example was I-66 inside the DC Beltway which is an HOV only route inbound in the morning. Navteq's data correctly identified the route and its restrictions, Garmin just refused to route using the road during the aggedted times.

This may be another case of Garmin not using the data from Navteq setting the restrictions.