Car Sharing


images-2I recently spent some time in Portland for a friend’s wedding.  A big group of us went and we needed to rent a couple of cars.  After talking about how expensive the car was to rent, it was suggested by a listener that we should do a podcast about car sharing.  Well – here is that podcast.

Car sharing is all over the place in Minneapolis, but I’ve never gotten close enough to using a car share to actually look into how they work or what they cost.  I decided to take a quick peek into 3 local options in Minneapolis:  Car2Go, ZipCar, and HourCar.  ZipCar and Car2Go are likely available in your area too if you live in a metropolitan area – check out their websites to see full availability.

All 3 companies do things a little differently, but the basic premise is the same.  You don’t have a car, but you need one, sometimes with zero notice.  Car2Go allows you to check your phone to see if any cars are available near you.  If you are lucky enough to be close to one, just walk up to it, swipe your Car2GoPass, and you are off.  ZipCar and HourCar have convenient fixed pick-up locations around town.  Reserve one, and pick it up from one of those locations.

When you are finished, leave your Car2Go in a valid parking spot (no need to return it to where you got it!), or return your ZipCar/HourCar back to the location you picked it up from.  Pretty simple stuff.

The Main factor that differentiates these 3 companies is the pricing structure.  ZipCar and HourCar have monthly/annual subscription models, and then charge around 8 bucks an hour or so while you are driving their vehicles.  Car2Go has a 38 cents per minute price that makes it really attractive for shorter trips, but also has hourly and daily rates if you need it longer.  2 plans cost money to join – 35 bucks for Car2Go and 25 bucks for ZipCar.  I couldn’t find an initiation fee for HourCar, so I can’t confirm if it is free or not (I doubt it).

Comparing the per minute/hour/mile/day pricing can be a bit of a hassle, I go into all the details in this episode.  Zach Shaner from the Seattle Transit Blog also did some similar research last summer and published a cool chart to help visualize some of the comparisons between Car2Go and ZipCar.  As you can see, with a cheap per minute rate but a more expensive per hour rate – Car2Go is a great deal for very short trips (< 25 minutes).  If you are using one quite often and use it for more than 25 minutes or so, you may want to look into one of the monthly plans from ZipCar or HourCar.


Check out the detailed pricing structures at their websites!

The Zipper Merge


What is The Zipper Merge?

The Zipper Merge, also called the late merge is a method for merging traffic into a reduced number of lanes. It is most effectively used in situations where there is a large amount of traffic.


What does the zipper merge accomplish?

Interesting, the zipper merge has not been found to increase the number of vehicles that pass a point over a given time period. But it does significantly reduce the length of the backup line (by up to 40%) and most importantly reduces the difference in speed between the two lanes, which improves safety.

One problem with the zipper merge is that it goes against what most people think is the polite way to merge into a single lane. In an effort to ease the concerns of your average driver, many states have campaigns to promote the zipper merge and in Belgium drivers are required by law to use the zipper merge! Two U.S. states that have published statements on the zipper merge are Washington and Minnesota.

The Minnesota Department of Transportation actually has a statement regarding the zipper merge. Sue Groth, MnDOT traffic safety and technology director was recently quoted saying “raising awareness for motorists to use the zipper merge in construction zones will help reduce crashes, speeds and congestion.” The zipper merge is even mentioned in the MN state drivers license manual.


The zipper merge code of conduct:

  1. Continue as long as possible on the merging lane;
  2. At about 300 meters before the bottleneck (marked with a traffic sign), adjust to the speed of the vehicles driving on the adjacent lane;
  3. Vehicles driving on the adjacent lane deliberately make room for the merging vehicle;
  4. At about 50 meters before the bottleneck, without braking or disturbance of the created space, the vehicle merges. Thus the merging vehicle and the vehicle behind it can continue their ride.


Where’s the data you ask? Check out this report from Wayne State University which was submitted to the Michigan DOT in 2007.

Their findings are summarized as follows: normal work zones with lane closures, drivers do not merge at any one definite point, thus causing sudden interruption in traffic flow and sometimes higher delay. The dynamic late lane merge system (DLLMS) was used to identify a definite merge point, improve the flow of the congested freeway work zones and reduce queue lengths in the freeway travel lanes. During the 2006 construction season, the DLLMS was implemented on three freeway segments in southern Michigan. Each work zone segment involved a lane closure from two to one lane. Based on the travel time characteristics, queue, merge locations, and throughput, the effectiveness of the DLLMS was evaluated by the Wayne State University Transportation Research Group. Before period data was not available, so a conventional work zone merge system located on EB I-94 was used as a control site for the WB I-94 test site. Since the two I-69 test sites are approximately 150 miles away from the EB I-94 control site, the I-94 control site could not be used as a control for the I-69 sites. When comparing the I-94 control and test sites, the presence of the DLLMS improved the flow of traffic and increased the percentage of merging vehicles that merge.

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