Not routing on Parkways

My NUVI will route me on a couple of local parkways, although in practice they are pretty indistinguishable from other roads. Any possibility that your parkways have sufficient restrictions (e.g. time of day, vehicle types) that they don’t meet some minimum criteria. I am assuming that your NUVI is aware of the parkways but just refuses to route them.

due to another restriction you have such as toll roads.

What exactly do we mean by "parkway"?

I agree, and the simplest test would be to remove all the restrictions temporarily.

I am pretty sure I have seen the toll road avoidance have effect on something with no toll on at least one of my units.

For example the Baltimore-Washington Parkway that runs from Washington DC to Baltimore. It's an alternate route than taking I-95.

I used to be able to take the parkways about a year ago then all of a sudden it with the most recent map udates it wants me to go only on I-95.

The parkways around here are not toll roads.

Next time I go I will remove all the restrictions and see what happens.

I think the routing is based on the posted speed limit. Since I-95 and the BW Parkway are adjacent and parallel, I-95 has a 65 MPH speed limit and BW Parkway is 55 MPH.

The GPS calculates based on your preferences, and you probably have it set to shortest time versus shortest distance, especially if you are approaching the Parkway on the Outer Loop of the Beltway.

As you state the problem is with the BW, it's easy to diagnose. The difference is the speed limits. The BW is 55 while I-95 is 65. The estimated travel times would be faster on I-95 and so a route using either fastest or shortest would bypass the BW unless the starting point was somewhere like Greenbelt.

You may still have an issue with faster time or shortest distance. You have to have your Nuvi set to one or the other.

I'd suggest you just select a waypoint on the B-W Parkway between your start point and your destination, if nothing else works. That way the Nuvi will have no alternative but to route you the way you want to go.

I just set my position just south of the BW Pky and chose the destination Baltimore City. My Nuvi took me on to the Pkw and proceeded on into the city. I have Quickest set and standard avoidances. No tolls. BTW, the speed limit on the PW is 55.

...but would TrafficTrends be causing this?
Also, I know it's not ideal, but if you calculate the route and then continually ignore it and still go on the parkway, myTrends should start pushing the preferred route to your personal preference, I think.

Troy's nuvi 670 has the avoidances feature. Can we set an I-95 avoidance or is this the same as every nuvi?

https://buy.garmin.com/en-US/US/on-the-road/discontinued/nuv...

dobs108

The BW parkway isn't always a viable option. It's 2 lanes in each direction and is subject to closure with almost any accident. With limited exits you can be trapped for hours (and many have) if you are between public exits. As the BW also travels alongside or near several government installations there are exits that aren't open to the public and are barricaded. You just need to pay attention to the traffic reports and base your choice on those.

I still don't understand how this works. I have fastest set and the Nuvi routes me to make multiple turns when there is a direct diagonal route.

How would Mapquest or Google Maps route you?

I only take the BW parkway once I am inside of the 495 Beltway. So it's definitely not the 55/65 difference.

When I am on the BW parkway inside the beltway the Nuvi wants to take me all the way out to 495/95 is only 55 on the beltway and once you get out of DC into MD on the parkway it's 55.

Google maps and mapquest always have me take the parkway until I get to the North part of the beltway and then it will dump me onto 495/95.

The Nuvi used to do this but it quit with the later updates.

I've been complaining about Garmin 660 routing for quite awhile now. Last trip to AC, NJ it did pretty good by sending me up the Eastern Shore, but it wanted me to go US 13 not 113. 113 is a much nicer drive with a lot less traffic lights, although you then have to get on DE 1 which is a toll road (2 $1 hits), but worth the time and fuel saved.

On the way back, for some reason it wanted me to use I-95. It's never done that before. Didn't take the "White knuckle" highway. Had to turn the routing off for a while until it realized that my way was now a better way.

Every time a new map comes out - they change the routing algorithms and you always get a surprise, the first time you take a trip.

Urm... No. The algorithms are in what Garmin calls the software, and the rest of us call the firmware.

The maps are data on which the algorithmns operate.

Which makes sense because the maps are purchased by Garmin from Navteq

If your diagonal route requires a left turn, most GPSs will avoid a left turn and instead route you through a series of right turns. The reason they do this is that it has been proven repeatedly by studies that right turn routes are almost always faster than a route involving a left turn.

Then explain how else the routing can change with EVERY map update. We're talking route changes on a 36 mile trip I make every day. There have been no physical changes in the route and no speed limit changes. The route Garmin wants me to take is 20 mph slower and is loaded with traffic lights. I use the routing for "Traffic Alerts".

On one map change, my 660 had me routed around my block the long way (0.8 mi. longer) on the return trip. The last turn before the driveway is 300 feet away, yet the 660 wanted me to keep straight for about .35 mi. and then turn and come back .45 mi. to the house (I'm on a corner lot and the block is roughly shaped like a triangle).

If you do a search here on algorithms, I think you will find a discussion where someone talked to a Garmin Tech about a routing problem and the tech stated that one of the programmers told him that they would fix the routing code on the next map release. Of course, it could be fixing something in the map, I admit that is possible.

I did a search on "routing" and came up with over 500 pages. Maybe the author will come forward and point us to the thread. It's been a few years back.

While the algorithms (formulas for calculating routes) don't change with a map update, changes in the map data (such as speed limits, road classifications, intersection rules, etc) can cause the gps to calculate a different route with a new map.

I have a Garmin Nuvi 255W running software version 760. This latest software version was released on March 2nd 2012 http://www8.garmin.com/support/download_details.jsp?id=4105

Between March 2nd 2012 and today Garmin has released 6 map updates. My unit does not have traffic trends, I do not use the traffic receiver and all avoidances have always been the same. After each map update I always perform a hard reset.

I've clearly observed that my unit will route me home from my workplace two different ways depending on the map set I'm using. As an example, map set 2013.10 will route me home a certain way whereas 2013.20 will route me home another way. Map set 2013.30 might very well route me home as did map set 2013.10

The routing it gives me to go home varies continuously back and forth using these two exact same routes from one map to another. There haven't been any new roads added from my workplace to my home and I've also checked the speed limits on both routes and they also haven't changed.

Conclusion: The routing with my unit will vary somewhat from one map set to another.

Cheers

You clearly state that 2013.1 routes a different way home from 2013.2. However you then say that Map set 2013.30 might very well route me home as did map set 2013.10 as opposed to saying it did route differently.

Assuming that you have installed each map update, was it different?

Can you determine that - at the start of each homeward trip - your vehicle was parked at the same spot? I ask this because before I retired I had an assigned parking spot.

1- I am always parked in the same spot at work.
2- The example of different routing is always from my workplace to my home since thats the only experiment I actually do and test from one map set to another each and every single time I download a new map.

There are TWO different routes my unit will have me drive home to and it all depends on the map installed on the GPS.

One map will tell me to take route A as an example. Another map set will tell me to take route B. Another map will tell me to take route A, another map will tell me to take route A, another map will tell me to take route B, etc.

Depending on the map set, the unit will suggest for me to take either route A or B, and it continuously varies back and forth with these two same routes.

I know for a fact having observed this that the route the unit tells me to take from my workplace to my home depends on the map the GPS is using.

I am learning so much from these threads. I am glad to see though I am not the only one who is experiencing issues.

I wonder if it could be that Garmin or the mapping folks blocked out routing on the Baltimore-Washington Parkway because no commercial vehicles of any type are allowed there.
http://www.nps.gov/bawa/faqs.htm
Knowing how literal some people are... Turn Right Now! /splash... they may be wanting to avoid putting a delivery person, charter bus driver, or cabbie in a ticket-able situation.

Google maps takes the direct rout while Mapquest has me making the turns but not the same ones as the NUVI.

my diagonal is on the right and goes straight to the destination. The route that the GPS uses has me making a right and then a left at a busy intersection with no lights. And it takes me to the same road that the diagonal gets to. The diagonal route is the fastest, shortest, and safest so I don't understand why it routes the other way.

Thanks for the info. I am now understanding that - starting from 2013.1 - the routing was
2013.1 route A
2013.2 route B
2013.3 route A
2013.4 route B
2014.1 route A
2014.2 route B
2014.3
where "A" and "B" are just to give them a name.

This is fascinating! I can not imagine why this would be the case.

I do not suppose that you have them, but it would be interesting to sit in your car at work and have a SD card with older maps available to use for routing.

With the most current map, simulate going home and look at it for a while. Then change the active map and simulate the other route. Does the routing start out the same and then deviate, or does it vary immediately?

It's interesting that they alternate each time. A road change would explain a change from one to the next, but if this is accurate, it stretches the hypothesis to see that it flipped back and forth each time like that.

I used to work in a regional software support center for a very large manufacture. There were two software development teams where each was working on their own next release of software. This arrangement almost always resulted in a few bugs that would only be fixed in every other software release. Same thing is probably going on with the maps.

It just seems to me every time an update happens. My routing ends up changing.

That is interesting indeed. I wonder if creating definitive global climate change models would be easier than figuring out Garmin's routing logic!

So yesterday I took off all avoidance. I was going from Anacostia Naval Base to Joint Base Andrews. Clearly the fastest and shortest way to get there would be taking Suitland Parkway.

My Nuvi wanted me to avoid that at all costs taking me a much longer route in distance and in time.

Every time I would come up on an exit on the parkway it wanted me to get off the parkway.

I just don't get it.

Pitch a bitch at Garmin about the routing failure. It has to be the way those roads are coded in the map database. That's something Garmin's developers do, not NavTeq.

FWIW, I just simulated the route on my Nuvi 2555 and it took the Suitland Parkway, no problem. Route=Fastest, Avoidances=U-Turns, Car Pool, and Unpaved Roads. 12 miles, 17 minutes. Also Advanced Detours. Maps=CN North America NT/ 2014.30 Lower 49 States.

have the same issues with any of my three Garmin units. I will be curious to hear if and how you resolve this matter. Thanks.

Maybe the Nuvi was thinking the same thing. It's

After all, (as Gallagher would say), "Why is it we 'Park' in a 'Drive'way... and 'Drive' on the 'Park'way..!!..?

Nuvi1300WTGPS

Troy, do you have the European maps installed? Is it possible for you to reload your latest map update and not include the European maps? It's possible some parts of the European data is causing a routing conflict.

I do have the European maps installed. But I can't figure why that would have any effect on the US Maps. I have my EU maps loaded on the card.

Another issue with map updates is you lose any routes that you entered. Yes, the routes you entered are still there, but it routes you in a straight line (i.e. as the crow flies). You have to download the routes from basecamp to get them back.

I need to learn how to do that. Sounds like it would make my life much easier.