Monday, September 30, 2013


If 100 people live on a circle 5 miles from church and they each drive 10 miles per week to and from church, that's 1000 miles per week, ie 50 gallons of gas at 20 mpg, ie $150/week at $3/gallon.

The circle circumference is 10Pi = 31.4 miles. If 20 cars move 5 people each, efficiently, they move 20x10 = 200 miles per week in and out + 2x20/100x31.4 circular miles, in a pie-shaped wedge, ie 451 miles per week, using 451/20 = 22.6 gallons of gas worth $67.70.

The weekly difference is $150-$67.70 = $82.30, ie $4280 per year, not counting reduced wear and tear on the cars or environmental benefits or increased socialization opportunities.

The basic economics make sense, but this needs social engineering, eg considerations of fairness, flexibility, privacy, safety, personality conflicts, and so on.

Why doesn't everyone car pool? How can computers help? Who travels with whom, and in what order? How can we avoid George feeling burdened, or personality conflicts with Alice? What happens if someone decides to skip church one week or only comes once a month or isn't ready to go when the driver shows up?

Poland had a national Autostop (hitchhiking) system in the 70s. A person by the side of a road would hold up a book with a target symbol on it, and a driver would stop and give her a ride, in exchange for a coupon torn from the book. The coupons were national lottery tickets redeemable by the driver. The trips were also insured for safety by the government.

At one point, the Israeli army mostly traveled by hitchhiking...

>... In Cuba, picking up hitchhikers is mandatory by government vehicles, if passenger space is available. Hitchhiking is encouraged, as there are few cars, and designated hitchhiking spots are used. Waiting riders are picked up on a first come first go basis.

>In 2009 carpooling represented 43.5% of all trips in the United States[1] and 10% of commute trips.[2] The majority of carpool commutes (over 60%) are "fam-pools" with family members.

>Carpooling, or car sharing as it is called in British English, is promoted by a national UK charity, Carplus, whose mission is to promote responsible car use in order to alleviate financial, environmental and social costs of motoring today, and encourage new approaches to car dependency in the UK. Carplus is supported by Transport For London, the British government initiative to reduce congestion and parking pressure and contribute to relieving the burden on the environment and to the reduction of traffic related air-pollution, in London.

>Challenges for carpooling

>Flexibility - Carpooling can struggle to be flexible enough to accommodate en route stops or changes to working times/patterns. One survey identified this as the most common reason for not carpooling. To counter this some schemes offer 'sweeper services' with later running options, or a 'guaranteed ride home' arrangement with a local taxi company.

>Reliability - If a carpooling network lacks a "critical mass" of participants, it may be difficult to find a match for certain trips. In addition, the parties may not necessarily follow through on the agreed-upon ride. Several internet carpooling marketplaces are addressing this concern by implementing online paid passenger reservation, billed even if passengers do not turn up.

>Riding with strangers - Concerns over security have been an obstacle to sharing a vehicle with strangers, though in reality the risk of crime is small.[12] One remedy used by internet carpooling schemes is reputation systems that flag problematic users and allow responsible users to build up trust capital, such systems greatly increase the value of the website for the user community. 

>Real-time ridesharing (also known as instant ridesharing, dynamic ridesharing, ad-hoc ridesharing, or dynamic carpooling) is a service that arranges one-time shared rides on very short notice. This type of carpooling generally makes use of three recent technological advances:

>GPS navigation devices to determine a driver's route and arrange the shared ride
>Smartphones for a traveler to request a ride from wherever they happen to be
>Social networks to establish trust and accountability between drivers and passengers

>These elements are coordinated through a network service, which can instantaneously handle the driver payments and match rides using an optimization algorithm.

>Real-time ridesharing is promoted as a way to better utilize the empty seats in most passenger cars, thus lowering fuel usage and transport costs. It can serve areas not covered by a public transit system and act as a transit feeder service. It is also capable of serving one-time trips, not only recurrent commute trips.Furthermore, it can serve to limit the volume of car traffic, thereby reducing congestion and mitigating traffic's environmental impact.

>One potential drawback may be economic harm to the auto industry due to sharing; however, some auto companies such as Daimler are quite supportive of real-time ridesharing research. Opposition may also come from taxi companies and public transit operators.


>Early real-time ridesharing projects began in the 1990s, but they faced obstacles such as the need to develop a user network and a convenient means of communication. Gradually the means of arranging the ride shifted from telephone to internet, email, and smartphone; and user networks were developed around major employers and universities. As of 2006, the goal of taxi-like responsiveness still generally eluded the industry; "next day" responsiveness was considered the state of the art.

>Most instant ridesharing services are still in their early stages. Successful pilot projects have been completed, but no real-time ridesharing company seems to have yet reached a critical mass of users.

>Two dynamic ridesharing pilots in Norway received government funds from Transnova in 2011. One pilot in Bergen had 31 passenger in private cars during one day. Thirty-nine users acted as drivers or passengers between June 30 and September 15 with four ridesharing episodes or more. The phone apps that was used was Avego Driver and cell client, a prototype developed for the NPRA of Norway. The other pilot is run by the company Sharepool.

>In France, real-time ridesharing is provided by Geocar from Villefluide, which focuses on the commute market and utilizes a cluster model and algorithms.

>Nous sommes spécialisés depuis 2008 dans les problématiques de déplacements liés au travail. Grâce à notre expertise, nous sommes capables de penser à l’échelle d’organisations afin de proposer à chaque employé la meilleure solution personnalisée de mobilité. Plans de mobilité, déménagements d’entreprises, covoiturage domicile travail, inter-modalité, VilleFluide est un acteur majeur de la mobilité 2.0.

"Notre vision est celle d’un monde où les déplacements du futur seront plus responsables, plus partagés et plus économiques. Notre ambition est à la fois de marier le meilleur des technologies à un concept entièrement innovant de réseau local de transport pour apporter des solutions de partage aux trajets récurrents, quotidiens, en relation avec tous les autres moyens de déplacements.

Nous poursuivons notre effort de R&D afin de toucher un public le plus large possible. En particuliers ceux qui ont un besoin fondamental de faire évoluer leurs pratiques de mobilité, pour des raisons économiques le plus souvent.

En vue d’atteindre cet objectif, nous nouons des partenariats stratégiques, avec des industriels, mais aussi des collectivités locales et territoriales, qui ont compris l’énorme bénéfice qu’elles pouvaient tirer de ces nouvelles solutions de déplacements."

>Wedrive est l’application grand public de VilleFluide. Il s’agit de la première application permettant de covoiturer vraiment chaque jour pour aller travailler.

Wedrive is Villefluide's smartphone app, which uses facebook.

A church transportation system with a fixed schedule and one fixed destination and fixed origins might not need GPS or smartphones, but it seems to need a mechanism for fairness, eg the Phoenixville Area Time Bank

If a driver (eg George) gives a passenger (eg Alice, who is unable to drive a car) a ride to church, and that takes another 0.8 hours, Alice could give George 1.2 hours from her time bank account (earned by babysitting or cooking?) , and George could get a different time bank member to mow his lawn for an hour.

If Alice is not ready to go on one Sunday morning when George arrives at her house, and that makes 4 people 1/2 hour late for church, Alice could donate 0.8+4x0.5 = 2.8 hours to the time bank that week, with an appropriate distribution to the accounts of George and the other 3 passengers. If George's late start makes everyone 1/2 hour late for church, George could donate extra time to the bank...



  1. Nathan Hurst says pink moustaches are popular in Seattle...


  2. Car2go is a fantastic business model here in Denver

  3. It's nice that you don't have to end your trip where you start, using Car2go.

    I'd like to see a system that facilitates random ridesharing with strangers to increase passenger miles per gallon, or erg.

  4. More: "How I Solved the Energy Problem." describes about 30 non-dynamic ridesharing services. describes how to upload addresses from a spreadsheet to a custom map. describes an API that finds all the distances between each pair of map locations. describes Noah, a dynamic large-scale real-time ridesharing system with a service guarantee on road networks. Taxis and trip requests are dynamically matched. A taxi can have more than one customer on board given that all waiting time and service time constraints of trips are satisfied. The system analyzer shows average waiting time, average detour percentage, average response time, and average level of sharing. Taxis, routes, and requests will be animated and visualized through Google Maps API. The demo is based on trips of 17,000 Shanghai taxis for one day (May 29, 2009); the dataset contains 432,327 trips. Each trip includes the starting and destination coordinates and the start time. An iPhone application is implemented to allow users to submit a trip request to the Noah system during the demonstration.