Sunday, May 30, 2010

How much does it cost to get around in the city: bikes, public transport and taxis compared

Melbourne's public bike share scheme starts tomorrow.

Each mode has its own advantages and peculiarities. For instance public transport isn't always door to door, waiting times for taxis varies, and the bike hire scheme requires a $300 security deposit (daily and weekly members only) and BYO helmet.

The charging structures for each mode varies, and this will be the topic here.

Taxi: Fares are based on a $3.20 flagfall plus $1.617 per km or 56.6c / minute time charge (the time charge applies if the speed is under 21 km/h). A 20% surcharge applies late at night or on public holidays. Taxi fares are several times dearer than public transport fares or bike hire charges, to reflect the personal door to door service provided.

Public transport: Fares depend on ticket type, validity period and passenger. Discounts apply for bulk-purchase, periodical and weekend tickets. A single-trip City Saver costs $2.80. 2 hours unlimited travel in Zone 1 (which includes the CBD and inner suburbs) costs $3.70, while a day costs $6.80. Concession fares are a bit over half these amounts. Bulk purchase and periodical tickets can offer savings of 25% or more.

Bike Share: Charges are based on a $2.50 daily flagfall (or membership charge) plus a rising charge per 30 minute block. The first half-hour is included in the flagfall. The next half-hour costs $2.00. Above then per half-hour charges rise; to $5 for 61 - 90 minutes and then $10 for each subsequent half hour.

Comparisons: Imagine a graph with time along the x-axis and cost along the y-axis.

The taxi curve is very steep, shooting up to nearly $10.00 by around 10 minutes of travel.

Public transport and bike share are both cheaper than taxis, but they swap places depending on the amount of travel time required.

Up to 30 minutes bike share is almost always cheaper, at $2.50 (much less for weekly and annual members). However users of City Saver x 10 pay $2.18 per trip - this is the only case where full fares are lower than bike share charges for up to 30 minutes of use. While the City Saver x 10 is a bulk-purchase product, there are no restrictions on when it must be used up by, unlike periodical Metcards or weekly bike share memberships.

The costs of bike share and public transport cross over in the 30 to 60 minute region. 60 minutes of bike share costs $2.50 flag fall + $2.00 usage charge, or a $4.50 total. In contrast a 2 hour full fare Zone 1 ticket costs $3.70. Hence for the casual pay-as-you-go user, public transport is always cheaper for an hour's travel.

It is in the 60 minutes or under usage level that the benefits of long-term bike share memberships are greatest. A weekly member riding up to an hour 5 days per week pays $1.60/day flagfall + $2.00, or a total of $3.60 per day. This is comparable to casual Metcard ticket purchase (for a 2 hour ticket) but dearer than a 10 x 2 hour Metcard. Yearly bike share membership is only 20 times the daily rate, so yearly members who cycle weekly or more would pay just cents for flagfall each time. Yearly members could bike share for an hour a day and pay less than public transport users, even those using periodical tickets. Around the 30 - 60 minute region bike share and public transport costs are roughly the same, with public transport generally cheaper, especially when compared against costs for casual bike share users.

Beyond an hour the cost differences between bike share and public transport diverge markedly. Because public transport tickets are mostly time-based, and the shortest is 2 hours, it is no dearer to take transit for 2 hours than it is for 1 hour. There is also a relatively gentle rise from 2 hour to daily fares, with less than a doubling for an increase in travel time allowed by over five times.

Bike share charges behave in the opposite manner, rise steeply with time of use. Charges (excluding flagfall) increase from $0 (30 minutes), $2 (31 - 60 minutes), $7 (61 - 90 minutes) to $17 (91 - 120 minutes). At this 2 hour level casual bike hire is $19.50, ie approximately 5 times dearer than a 2-hour public transport ticket. This almost exponential rise is presumably to encourage use of the scheme for short trips in the CBD region only.

Conclusion: Of the three modes of travel compared, public transport is the most cost-effective for CBD travel. This is especially for visitors from the suburbs, who in many cases will have arrived on public transport with a daily or higher ticket, so would face a marginal cost of further CBD travel of zero. The bike share scheme occasionally works out cheaper, but only for those frequently making short trips.

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Sunday, May 09, 2010

Effective Frequency - a measure of timetable co-ordination

One of this blog's hobbyhorses, that of timetable co-ordination, made it into today's Age. Not only that but it even got a one-liner on Gold 104 News (heard while travelling on the 901 SmartBus if anyone asks).

The above link has a spreadsheet prepared by the PTUA. There is also a web application showing average connectivity by route and station (note: timetable data from last year).

More buses and timetable co-ordination were cited as ways to improve connectivity. Though the article focused on buses, train frequency can also be part of the solution, especially in outer areas where hourly minimum standards buses cannot connect with trains every 40 minutes and middle suburbs where SmartBus and train frequencies don't always match.

Average connection times provide a rough guide, but as they say, 'your connection may vary'. Provided headways are fairly constant (which they are for most services), a measurement method I like is the concept of 'effective connected service frequency', most commonly for a suburban bus feeding a city train.

Let's take Route 436 at Werribee, a local route that scored well for connectivity. As the service is headway harmonised with trains throughout the day and connections are good, the effective connected service frequency of a train+bus trip is the same as the bus route's individual frequency (in this case 40 minutes) seven days per week. This is how it should be for an effective network.

A similar suburb to Werribee, but in Melbourne's north, is Craigieburn. However its buses operate at frequencies incompatible with trains. Therefore passengers need to be choosy about what services to catch to minimise waiting.

A sample of Saturday train/bus times ex city are as follows:

Train arrives 9:52am

Bus 528 departs 9:57am

Train arrives 10:12am

Bus 528 departs 10:27am

Train arrives 10:32am

Train arrives 10:52am

Bus 528 departs 10:57am

Train arrives 11:12am

Bus 528 departs 11:27am

Train arrives 11:32am

Train arrives 11:52am

Bus 528 departs 11:57am

With a 10 minute maximum waiting time allowance, the effective connected service frequency is only 60 minutes (connecting services shown in bold), despite each part of the network operating more frequently. Even though Werribee's local buses are less frequent than Craigieburn's, Werribee's effective frequency is higher due to better connectivity. Werribee passengers get a good connection every second train, but for Craigieburn it's every third train (this is on weekends, on weekdays Werribee has a higher train frequency).

Pakenham on weekends has similarities to Craigieburn. The difference here is that the frequencies are halved - trains every 40 minutes and buses every 60 minutes. The effective connected service frequency ends up being two hours because of unharmonised scheduling. Not exactly attractive for your discretionary passenger, and inferior to the planned connectivity that hourly minimum standards routes were intended to give.

Everyone knows that frequency is key to attracting patronage. At the same time buses cost money to run, so it is not always possible to deliver the highest frequency.

However effective service planning requires that the effective connected service frequency is no worse than feeder bus frequencies to maximise network connectivity and thus patronage. Not doing so means that taxpayers are paying for a higher service frequency than can be realised and passengers are getting a lower overall frequency than ought to be possible given the number of buses on the road.

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