Analysis of Google’s Bike-There Feature: Part I

Analysis of Google’s Bike-There Feature: Part I

Posted on 06. Apr, 2010 by in Mapping

It’s been nearly a month since Google made their game-changing announcement about the addition of a “Bike There” option to Google Maps. Since that time, there have been numerous reviews and assessments about the utility of the new application – some positive, but also many that point out the limitations of Google’s new tool. Many people have noticed that Google sends them on roundabout routes or through inaccessible places, while others have had more success. Therefore, you might be wondering at this point whether or not Google is the best resource available for figuring out what route to take in order to get from by A to point Z (and beyond!) by bike. In this series, we are going to try to help answer that question and attempt to determine if Google is the best available resource for bike mapping and route-finding at the moment, what are its advantages and disadvantages, and what other resources are available for finding a good route by bike. We will begin by reviewing the Google Bike-There feature and the main principles that Google’s engineers used to build the algorithm that spits out the directions. In following posts, we will review other bike mapping tools, which we will compare and contrast to Google’s Bike-There feature, and try to determine the best method for mapping bike routes. Our goal for this series is to provide some insight into the challenges and issues of bike-route mapping, and we hope that you join the discussion in the comments section. (Header photo credit – Chloe Forsman).

Behind the Scenes – How Google’s Bike Maps Work

The push to get Google to incorporate bike directions into Google Maps has been going strong for quite some time now, but Google reports that adding such directions presented quite the engineering challenge. Google uses a few key features to develop the algorithm that generates a bike route, using the already-existing network of streets in their mapping system, which are summarized below.

  1. Bike Trails – These show in dark green when you generate a Bike-There map. Google worked directly with the Rails-to-Trails Conservancy to find as many trails to incorporate as possible. The algorithm is weighted to send cyclists on trails as much as possible, as long as it doesn’t send them too far out of the way.
  2. Bike Lanes – Google has information about dedicated bike lanes for 150 U.S. cities, which they used to build into the algorithm. Bike lanes appear on a Bike-There map in bright green, and they are also weighted as a priority in the algorithm.
  3. Recommended Routes – These are routes from cities that have information about other good roads for cycling, which may not have an official bike lane. These roads are indicated by a dashed green line in the Bike-There map.
  4. Uphill Slopes – In order to avoid hills (because, according to Google, nobody likes riding up hills… though I beg to differ…), Google developed a model that takes into account power (exerted by the cyclist), the slope of the road, wind-resistance, and speed. If the model shows that a given route requires an inordinate amount of exertion (aka too much power required) and will be too slow for time efficiency, Google will send you on an alternate route that avoids the climb. I could not find out what Google defines as “too slow” or “unreasonable degree of exertion”.
  5. Downhill slopes – The model will also help cyclists avoid roads with too much downhill or descending, which can be tiring or disconcerting due to the unnecessary amount of braking required.
  6. Busy roads – In order to keep cyclists off busy roads, the algorithm basically uses the inverse of the Drive-There algorithm in order to avoid arterials and freeways.
  7. Intersections – Lastly, the algorithm avoids busy intersections with heavy traffic (car) and long waits.

If you want to read this information directly from the horse’s mouth – click here. It is important to note that this system is still in beta, and Google is continuing to add and update their maps using feedback from users. So if you found an issue, make sure to notify them.

Picture 2

Review of Google’s Bike-There Features

I must admit, I have a few opinions on the underlying principles that Google used to develop their algorithm. However, I am certainly not an expert in building such algorithms, and I realize the inherent limitations and difficulties of undertaking such an engineering project. Nonetheless, there are some underlying biases and (possible) misconceptions about cycling built into the algorithm, which make the Bike-There feature unappealing to me in some ways.

Picture 1Google Maps Bike Routes around University of AZ

First, I am curious about Google’s decision to avoid major intersections. When I experimented with numerous routes that I use in Tucson, I discovered that Google’s directions, do indeed, avoid major intersections. However, in doing so, the directions take a route that requires crossing major roads without the benefit of a traffic signal found at an intersection. Sure, the directions managed to avoid the major intersections, but it’s not always the best riding habit to avoid such areas, which, at least in Tucson, often have infrastructure in place for cyclists to trigger the traffic lights and cross safely when the light is green instead of darting across four, fast lanes of traffic. How do you feel about the avoidance of major intersections where you live?

Second, I have a little trouble with the prioritization of bike trails over established bike lanes (and/or recommended routes). According to Elaine Filadelfo, a Google Maps spokeswoman:

It„s a pretty complex algorithm that looks at all of the variables [including hills, traffic, road type and many others] and tries to come up with the most efficient final route. For example, it will prioritise putting you on a trail or a road with a bike lane and weigh that against how far out of your way it might send you or how hilly that terrain might be. We look at all of the variables in conjunction, but I would say the strongest factor we look for is to put you on a bike trail. (via Bike Radar)

At least in Tucson, the official bike trails are often quite congested with pedestrian traffic (usually of the recreational nature), which can make commuting somewhat more time consuming, as one has to ride slower. Given that a city like Tucson covers a large area (as do many U.S. cities), efficiency in bicycling can be quite important, so prioritizing bike trails over bike lanes can be somewhat problematic, especially in circumstances where bike trails are congested or out of the way.

Finally, I would love to know more about Google’s model to avoid uphill slopes. If anyone knows of any additional information, I’d appreciate your insight.

In general, and despite my criticisms, I think Google is off to a great start. In fact, it’s quite incredible that Google has finally incorporated bicycle directions, and I am looking forward to the impending improvements. I completely agree with Peter at GoogleMapsBikeThere, that because almighty Google has acknowledged the importance of bicycling directions, more and more influential groups and people are going to take note. So, thanks, Google!

Next up, we will review other bike route mapping tools, as a matter of practicality. What’s the best way to get from point A to point Z by bike?

16 Responses to “Analysis of Google’s Bike-There Feature: Part I”

  1. ga73

    06. Apr, 2010

    I find that the gmaps-pedometer is nice because it’s just a double click of the mouse to create your own route if you are more or less familiar with the area. I like google maps because it automatically finds some way to go between areas that I don’t normally travel. I was thinking about biking from Ithaca, NY to Washington and used google maps and noticed a lot of fun looking trails that I would not have otherwise thought of.

  2. Melanie Meyers

    06. Apr, 2010

    Hi ga73,

    Thanks for the comment. Gmaps Pedometer is a really useful application, as well. It is a hack of Google’s mapping application and uses Google maps as an overlay. It’s actually been associated with Open Street Maps (which I’ll talk about in a later post), as of late. It’s good to hear you found the Google maps useful for finding bike trails in the first place. That’s a great point and one huge advantage of the new Google tool.

  3. Richard Masoner

    06. Apr, 2010

    I really like how Ride The City lets you select Direct, Safe, and Safest (though I’m far from a fan of their nomenclature). The selection changes the weight of bike facilities — direct assigns them equal weight as any other road, safe assigns them a moderate weight, and safer assigns them the greatest weight (where “weight” is graph theory terminology for the preference to put on a particular path).

    In my area (Silicon Valley and Santa Cruz), the arterial and major intersection avoidance is a fail. The Santa Clara County Expressway system has roads that provide wonderful arterials for cyclists, and some of these roads are favored by cyclists of all levels yet Google Maps avoids these roads on their route making. In Santa Cruz, many of the streets are likewise just as bike-friendly as the bike paths — I can see giving a slight preference to the path system there, but not going a mile out of the way just to avoid certain roads or intersections. I’ve provided feedback to Google on specific routes.

    Thank you for the link love to my initial Google Bike There look. I also posted a Google Maps “Pro Tips” of other helpful hints.

  4. Melanie Meyers

    06. Apr, 2010

    Hi Richard,

    Thanks for your comment. Ride the City’s model is also quite useful, though I agree that the nomenclature is indeed problematic. It’s interesting to hear that you have had similar problems with the Google avoidance of major intersections, and I wonder what their main reason for doing that was. Nonetheless, I think we can all look forward to Google improving the algorithm over time through the user feedback. Also, thanks for the link to your Pro Tips blog, which is very useful. Thanks!

  5. Paul Johnson

    06. Apr, 2010

    If you want to contribute your information to a map, without having to give ownership of the data you’re contributing for free to some company who will make money off it, consider giving the information to OpenStreetMap.org instead. Then it’ll appear on OpenStreetMap, OpenCycleMap, and you can load that data on a Garmin at http://garmin.na1400.info/routable.php and get live, turn by turn bicycle directions. All around a better option than giving your data to Google for this problem.

  6. Melanie Meyers

    07. Apr, 2010

    Hi Paul,

    Thanks for the comment. We are going to cover Open Street Map in an upcoming post, and I’ll be sure to encourage our readers to submit their information there. Open Street Map is definitely a great idea!

  7. [...] Cycling Analysis of Google “Bike There” option part 1. I’ve submitted a number of corrections and gotten a response on two so [...]

  8. Rob

    08. Apr, 2010

    Where I live (Cleveland) the Rails-to-Trails directory of bike routes is extremely limited. The local planning agency (NOACA) has much more comprehensive bike maps – I only hope Google works with them in the future to develop their system.

    Another thing I noticed is that for longer rides, Google Maps sometimes routes you through dicey neighborhoods. Although not much of an issue for me, I imagine many suburbanites looking at the suggested route and saying, “no way am I riding through that part of town.”

  9. Melanie Meyers

    14. Apr, 2010

    Hi Rob,

    Thanks for the comment. I was curious about how prolific the Rails-to-Trails bike route directory is for the whole U.S. For the most part, it seems that, as you point out, certain areas are not well covered while others are. It might be mutually beneficial for Google and Rails-to-Trails to improve the directory, as well as beneficial to cyclists, but in the meantime, it seems like Google’s use of Rails-to-Trails might be limited in its utility.

    The point about riding through dicey neighborhoods is also an interesting one. It’s certainly the case that even a great map can’t really show you what’s going on on the ground, and it would probably be impossible for Google to ground-truth all of their routes to avoid dicey neighborhoods. And I do wonder what their stance on that issue is.

  10. [...] creating navigational tools. Google’s recently launched bike mapping feature has come in for some criticism because it doesn’t always incorporate such human knowledge; it remains to be seen if it [...]

  11. Inner Prop

    30. Jul, 2010

    One thing I noticed is that when you switch to bike function it shows the bike routes/trails, but when you go to print the “Big Map” they drop out.

  12. [...] between mapping technologies and cycling. Here are a few examples of Melanie’s best work: Analysis of Google’s Bike-There Feature: Part I, Part II and Part III Thoughts on Re-Imaging the Bicycle General Bicycle [...]

  13. Kate O'Neill

    14. Nov, 2010

    It seems to me that there are at least two major use cases for bike directions: one covers the experienced “hardcore” cyclist who would prefer the faster route, possibly including hills, and is potentially used to dealing with greater amounts of car traffic along the route. The other covers riders more like myself, who are more casual urban cyclists, commuting for practical purposes and who appreciate the efforts to make the route as easy and safe as possible. Perhaps they could add a preference, as they do with driving directions and highways, that would get at that distinction.

  14. GiaScott

    28. Jan, 2011

    My first experience with computerized mapping for bikes is with Google, as I’m new to the area and relatively new to biking. I needed efficient routes to get me to addresses I was unfamiliar with, and Google did the job, although it did NOT avoid some nasty intersections for me. As for dubious neighborhoods–what’s dubious on a bicycle and dubious in a car aren’t even close. Being unfamiliar with the area, I stuck to main roads on route choices rather than routing through neighborhoods that might present difficulties. Main roads are also more likely to have a broad shoulder suitable for riding rather than being forced to ride in the traffic lane with the motorized vehicles.
    Google’s bike map option isn’t perfect, but its in beta, and it is better than nothing. With a little common sense, some luck, and a bit of research, it does offer some great routes that we may not have chosen when armed with just a map. As bicyclists become more common, more vocal, and more demanding of accomodations, perhaps we’ll see better routing options for everyone, including a place to secure bicycles near businesses!

  15. the pilatesbiz

    08. Feb, 2012

    I would just like to let you know hvow much I learnt from your writtings Tweeted you.Hope 2 be back in the near future for some more good stuff

  16. [...] options on the internet, and it has a cycling friendly spin-off called Open Cycle Map. GoogleMaps also used a feedback option when they first launched the bike directions feature in 2010. And you can still request that they [...]

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