There is vast overlap between the fields of Traffic Engineering and Transport Planning. I, for one, am always at a loss as to what to call myself. Traffic Engineer gives the impression that I only deal with cars, while Transport Planner makes people think I've done a Planning Degree when in fact, I am a Civil Engineer.
The discipline covers all aspects of travel behaviour, all modes, all purposes, all aspects of the logistics. For example:
The only exception appears to be Air travel. To date, this has been the remit of Airport Engineers
, as the sheer scale of matters places the field in a category of its own.
A Traffic Engineer would be interested in all of these. Perhaps the best way to describe the myriad things that a Traffic Engineer does would be to consider a few case studies.
Case 1: New Office Block, City Centre
Microsoft™ want to build a new office block on Ground Zero. The Traffic Engineer is not concerned that Bill Gates wants to build the new tallest-building-in-the-world on the site. It is for the Architect, the Structural Engineer, or Bill's wife to point out that perhaps Bill isn't the most popular person in the world and maybe it's not such a good idea to tempt Linux-preferring pilots like that.
All that the Traffic Engineer is concerned with is the size of the development, the type of activity that it will house, and the surrounding transport links.
Glaring Assumption #1
A few assumptions transform [land use] * [area] into the number of person trips generated by the development. The previous tenant at Ground Zero, we now know, had to get 50,000 people into and out of the front doors every day. Let's assume Bill's office block has just as many workers.
At this early stage, we don't know if Bill's tenants will operate strict 9-5 hours, with all 50,000 people arriving at 8:55am and leaving at 5:05pm, or if they'll allow flexitime, meaning that only 50% (say) arrive between the peak hour of 8-9am and leave during 5-6pm. To get around this, we use "average" values observed at similar developments.
Glaring Assumption #2
Of course, if we can get most of the people in and out during the busiest hours of the day, then we can easily get the rest in and out during the rest of the day. Hurrah! We only need to gather data and analyse 8-9am and 5-6pm. (Note: in a congested network, such as London, the Peak Hour concept has been replaced by the 3-hour Peak Period: 7-10am and 4-7pm.)
Methodology (aka Glaring Assumption #3)
We're gonna go out and observe how many cars, buses, trains, trams and heliports currently pass our site. Then we're gonna put together some nifty little models of the roads, train lines, bus routes and sidewalks and calibrate them so that the models show what we observed outside.
For something Microsoft™ scale, we're definitely gonna have to call in the big boys. The local Planning Department will not let us get away without modelling at least all of Manhattan, possibly all of New York City. In fact, the local Planning Department will probably have to yield to the state Planning Department on this one. A development of this size could really screw up the entire transport network. It's no good showing that the intersection outside the front door is hunky dorey if all the bridges are blocked back for miles.
Next, we borrow the New York City traffic model and update it to our base year (this year) by going out and counting cars on all the major roads throughout the city. We're using kick-ass software, so the model not only has cars, but also buses, trains and trams in there. We're gonna need to do some serious surveys: counting people on trains, getting on and off buses, figuring out how many people ride in each car. The model will work on person trips, not vehicle trips, so if we're going to model interchange (Park and Ride), then we need to know how many people get out the car to get onto the train or bus.
Modelling is not an exact science. It is also a discipline all of its own. I personally am in grave danger of being labelled a Modeller, which is one rung above Trainspotter.
Now that we have our nifty base year model, where to from here? Well, now we add our development, apply traffic growth, include any proposed changes in the transport network, and hey! presto!...
... we've screwed up the system, there's traffic backed-up for miles and the buses and trains are all full.
Back to the Drawing Board
So what now? Bill Gates has to dig deep, I'm afraid. He can't just build his office block, he has to build some infrastructure to get people to them too. He also has to rethink that fifteen storey car park. Kids, you can't all drive to work. There just isn't space on the road!
Option A: Train
Bill can strike a deal with the local train company whereby he supplies MS Office© and installs Windows© free of charge on all their computers forever more, if they sign up to his support contract and build a station underneath his building. The train company think long and hard over this, but then realise that they can lie about the number of computers and sell off the excess licenses, and agree on condition that Bill pays for the re-routing of the tracks and builds the station himself. Everybody's happy.
Option B: Bus
Bill pays off the local Planner and convinces him to declare all major routes within five miles of the site as Dedicated Bus Routes. He then visits the bus company, offering to write them some nifty new ticketing software (which he holds the rights to) on condition that they supply three times as many the buses to his site. Everybody's happy, especially the local Planning guy.
Option C: Tram
Okay, okay, you've got it!
Not worth the paper it's printed on but oh-so-politically correct (aka Glaring Assumption #4)
The Mobility Plan. Previously known as the Green Travel Plan. These things are catching on like AIDS in Africa. The Mobility Plan is a document of unenforceable promises to make people travel by sustainable modes. The car is evil, public transport is king! Eg:
- Proposal 1: Appoint a Travel Co-ordinator
This do-gooder will keep a library of public transport information and tell you the best way to get to the office without using your car. If you live within 2 miles, you're walking baby. Up to 5 and it's hit that bike. No, not bike, bike.
- Proposal 2: Implement Flexible working hours and Teleworking
- Proposal 3: Car Pooling
Do-gooder sets up a car pooling database and organises it all. Great for big offices in suburban areas, not really of any use for our Ground Zero site.
- Proposal 4: Public Transport Subsidy
Heh. Please remember that the UK is supposedly a Socialist country. I live and work there. Essentially, Bill approaches the body who distributes the income from sales of Integrated Tickets (a single ticket to be used on all modes, usually season tickets) and says he'll write the software, if they give him a 25% discount on all season tickets he buys. He then sells the season tickets on to his employees at a 20% discount on face value and everybody's happy.
You get the picture? Goody.
Glaring Assumption #5
We now pull together the above and throw it all into our future model and hazah! It works! Whether it truly is feasible matters not, because a development of that size has all manner of social and political benefits. People always find a way to work and home and are surprisingly tolerant of travel delay.
Case 2: New Tram, Dubai
Sheikh Makhtoum al Makhtoum is very happy with the way his Emirate is developing. Shelling out all that money to dig Jebel Ali all those years ago has reaped huge dividends, even though he's forgoing all the tax he could be raking in on ex-patriots' salaries and companies housed in his Jebel Ali Free Zone. The important thing is that Dubai is making Sheikh Zayed al Nayan's Abu Dhabi look like a sleepy rural town, meaning that in the next century, when the US's oil has dried up and solar powered cars have rendered Sheikh Zayed's oil reserves almost useless, his offspring are going to rule the roost in the United Arab Emirates council. Hurrah! for forward thinking. (Well, that's what his son, Sheikh Mohammed told him, anyway.)
But hang on a tic, why does Sheikh Makhtoum want to build a tram if he gets his oil for free? His people don't mind, it only costs them US$15 to fill up the tanks on their big 4x4 LandCruisers. What's the go?
Well, Pakistanis make the world go round, especially when you only pay them US$50 a month and your world doesn't extend beyond the slums you own down the road in Sharjah and your 20 room mansion in Jumeira Beach.
US$50 a month? US$15 to fill your tank? Um. How do they eat? Answer: they take the bus.
The roads of Dubai are getting pretty full with Emiratis driving their LandCruisers, chatting away on their mobile phones, and these 50 year old stinking buses are seriously getting in the way. Sheikh Makhtoum is doubling the size of the Jebel Ali Free Zone and somehow needs to find a way of getting twice as many Pakistanis from Sharjah in the north down to Jebel Ali in the south, a distance of about 35 kilometres.
So, a tram. Splendid. Problem: Sheikh Makhtoum is going to have to fork out US$1,300 million for this tram. For a man who hasn't bought a bus in 50 years and gets his fuel for free, you're going to have to be pretty convincing.
Enter the Traffic Engineer!
Cue Superman music
- Bring back the old (actually new, but that's another node altogether, which thankfully resides in Node Heaven) Dubai traffic model.
- Write some kick-ass macros that niftily demonstrate every single Pakistani in the UAE switching off the bus and equally scary shared taxis and onto the tram.
- Call in the Economist, who does some funky calculations about Value of Time, Cost of Congestion, Cost of turning the already 4-lane Sheikh Zayed Road into a 6-lane superhighway, do some funky comparisons and hey! presto! My Man Makhy coughs up.
That, my friends, is the essence of Traffic Engineering. Highway Engineers design the actual road -- how to get the big ass articulated vehicles around that tight corner that the Traffic Engineer put in, what to put underneath the blacktop to make sure it doesn't get rutted, all that is somebody else's problem.