When you are travelling to a new city what you pay attention to likely indicates what you find most interesting in life. Some people notice food, some people talk about a cities architecture, or parks, or monuments. For a civil engineer, it’s impossible to move around a city without paying attention to infrastructure; rail, roads, utilities, really whatever is different from what you are used to seeing.
This past year I was sent to Taipei on business and spent some of my downtime walking the very large downtown and outer boroughs. The city is an interesting mix of old form planning design and newer innovative infrastructure that meets the city’s unique needs. It has many of the similar traits of other cities; a strong interconnected rail system, high density commercial business district, highways feeding into the city, and a myriad of different street sections ranging from 8-lane urban arterials to 1-way alleys.
During my time in Taipei I noticed one thing that puzzled me at the time. They have roads, some of which were 8-lanes of truck/bus/rush hour commute thoroughfares and yet, the city was walkable. Crossing these streets was easy.
Here is why I think Taipei can get away with this non-human scale infrastructure and still remain pedestrian usable.
- People on foot are plentiful. Sometimes when you are crossing a street, all you really need to stay safe is a bunch of other people. The chances of a driver not seeing multiple people crossing a street, versus one lone straggler, are far less (of course). This is why you rarely hear about multi-person vehicular/pedestrian incidents. This is obviously the hardest element to recreate, but perhaps the following design criteria will help get to this point.
- Lighting. I’ve said it before, and I’ll say it again, cities are a terrible place to start worrying about the circadian rhythms of moths… I’d much rather worry about the life-cycle of the human. Vision is the #1 factor that differentiates a dangerous intersection and a safe one.You can’t force people to wear yellow illuminating clothing. Yes, everyone should try to wear bright colors when crossing the streets, but honestly sometimes circumstances at work change; perhaps you didn’t know you’d be staying late and now you are walking across a dark road with all black and there’s not much you can do about it.Looking both ways, paying attention, of course is paramount, but there still remains times when vehicles turn out of a shopping center, or are making a U-turn, or a number of other scenarios where no one is really at fault, just circumstance. In a city, good lighting saves lives.
- All Reds. The bane of all transportation planners, atleast those in traffic modelling, is the all red traffic signal. This is exactly what it sounds like. Traffic for vehicles in every direction is halted, and pedestrians are allowed a cycle (usually between 30 and 45 seconds) to move in any direction they want in the intersection (yes including diagonally). The reason why so many traffic modelers hate using this signal form is because in their models, they are not allowed to have a cycle back function for the demand that is created. In other words, the amount of cars on the road never change no matter what “kind” of road they design. If they create a urban oasis of walkability, based on the current modelling method, they have to assume that the area continues to generate traffic at the same rate; no drivers are converted to walkers.Of course this is illogical, if you make an area more urban, some of the people who live or work in the area will switch from cars, and that is precisely the danger of this modelling method. There is no design benefit for anything except more pavement.So here you have an intersection, which during 30-45 second cycles, no one moves. This drives the traffic modelers crazy, even though this design makes a safer intersection and induces more people into walking, which thereby reduces traffic.
The point isn’t to use this at every intersection. Some cross-roads are smaller and more manageable to cross without the need for an all red. This is for mega-intersections; where 6 or 8 lanes intersection another road of 6 or 8 lanes and in the middle is a vast plain of asphalt.
- Striping-striping, everywhere. How can you expect people to cross at the right place, if you don’t provide proper signage and painting
It’s no wonder that in Taipei I felt perfectly safe at 10 o’clock at night crossing a 120′ wide downtown intersection and yet here in Tysons I would never even think about crossing International Drive and Chain Bridge Road, even in the middle of the day. Yes there is a cross-walk (on half of the road atleast), but other than that this intersection doesn’t meet any of the standards listed above. This intersection is going to be an important one when the Silver Line opens.
Thousands of guests stay at the Courtyard Marriott every month, and many more will likely stay there after the Silver Line opens, because on paper it looks so close. A lack of a safe intersection, unsafe for anyone who lives here let alone being new to town, is not a good combination for spreading the word about your urban city. Beyond this there are many office buildings across the street from the Silver Line Tysons Corner station.
This intersection today is one of the least congested in Tysons. In the Chain Bridge direction congestion is more related to the reduction in lanes as Route 123 enters Vienna than with signal timing. International Drive has some problems at times, but has less traffic demand than Chain Bridge Road and often is congested due to bigger problems on 495.
Maybe a compromise for now, until some of the redevelopment in the area takes a hold could help improve the safety situation. Instead of making a 45 second all red, start dealing with lighting, add a cross walk in each direction, and disallow turning right on red at this intersection. No all red means no diagonal crosswalk, but atleast the vision in this intersection is addressed and the most dangerous of all conflicts, the roll through red-turn is explicitly deterred. Add in the sidewalk needed along International Drive, and at a minimum to the metro station along Route 123, and you have an improved situation from today for minimal cost.
In the future, if more people appear to be using this intersection, an all-red could be incorporated, a far less costly and more urbane solution than a sky-walk, but future perfection shouldn’t be the enemy of improvement today. Lighting and signage is so simple and affordable compared to the other things occurring around town, we just need to light a fire under those in charge to start focusing on the little stuff.