For a long time now, the purpose of roads was to get people in cars to their destination as quickly and efficiently as possible. This is why we have highways, they're all about moving cars long distances at a fast rate. But recently, cities have started reclaiming roads as places for pedestrians, cyclists as well as vehicles. But this has meant slowing down cars to accommodate slower modes of transportation.

The arterial roads in Phoenix, for example, are on average about the size of highways in other parts of the country and the world. Sometimes an arterial in Phoenix is 7 lanes wide, with three lanes going either way and a middle turn lane. This ample room for cars ensures that cars move along the roads very fast.

Sounds good right? Well, not if you want your city to be people-oriented instead of car-oriented. A car-oriented city is focused getting cars from point A to point B, and so everything is about large obstacle-free roads, more highways and ample parking space. A people-oriented city, on the other hand, is about creating spaces for people to walk, bike, stand, sit and gather in the public in ways that are safe and enjoyable. It's about making the city accessible and safe for people to inhabit outside of their cars. It's not so much about moving people along as it is for creating a space for humans to be humans, whether they are moving or not.

Slow traffic is not only good for encouraging street life, it's also good for motorists, believe it or not. Slower traffic results in fewer accidents. The Sierra Club notes that, "recent studies have shown that narrow streets slow traffic and reduce vehicular crashes, increasing neighborhood safety." Often times, we think that the obstacle-free, wide street is optimal for driving. But in reality, that kind of street only encourages faster traffic, which may seem good is you're running late, but it's bad for traffic safety, neighborhoods, getting people to walk and bike, and the general appeal of a city.

So what are some ways for a city like Phoenix with 7-lane arterials to slow down traffic?

Here are 12 ideas:

1. Add bike lanes. Often times, motorists object to streets being narrowed and bike lanes being added precisely because it achieves its intended purpose – it slows down traffic. Cyclists on the road force motorists to slow down and pay attention. Bike lanes not only narrow the road, but they add cyclists to roads, which are a sort of "obstacle" for motorists to navigate, which means they have to slow down.

2. Add parallel parking. Though adding more parking is not an ideal way to slow down traffic, in many places in Phoenix, this would be a first step in slowing down traffic. Cars parked on the street effectively narrow the street and once again add an "obstacle" that cars need to slow down and be aware of.

3. Add roundabouts. Roundabouts force cars to slow down because they can no longer go in a straight-line. Roundabouts can be large enough to be public parks in and of themselves or they can be so tiny they can only accommodate a skinny tree. Either way, roundabouts make cars slow down.

4. Add trees. Planting trees close together makes drivers feel as if they are going faster, so they slow down. In the UK, more than 200 trees were planted on the approach roads to four rural villages in north Norfolk which had a history of speeding problems. The experiment was carried out by Norfolk County Council at a cost of £70,000, funded by the Department for Transport. Provisional results found that drivers reduced their speed on the roads into Martham, Horstead, Mundesley and Overstrand by an average of two miles per hour.

5. Add crosswalks. Painted crosswalks signal to pedestrians that they can cross the street. But on really fast arterials, HAWKs, or lighted crosswalks, that trigger a red light when a pedestrian or cyclist pushes a button are more useful. Pedestrians crossing the road make motorists more wary and force them to slow down. Crosswalks and HAWKs encourage more pedestrian activity.

6. Narrow the street with sidewalk neckdowns. Crosswalks are most effective when the street is narrow. So neckdowns or sidewalk bulbouts are a great way to narrow the street AND add more space for pedestrians on the sidewalk. Intermittent neckdowns that alternate down the street, or chicanes, are even better because they add unpredictability to the road which makes drivers slow down and pay attention. Mill Avenue in Downtown Tempe has some good examples of successful neckdowns.

7. Eliminate bus turn-offs. Bus turn-offs are where buses have an additional space on the road to pick up and drop off passengers. Again, this sounds fantastic if you want to speed up traffic. But if you want to slow traffic down, it's important to incorporate the pace of transit and people into the natural flow of the street. Sure, a stopping bus in front of you is annoying, but it does serve to slow traffic, which is what we're after.

8. Encourage sidewalk cafes. Sidewalk cafes add visual interest and a human scale to streets. A good example of this in Phoenix is on McDowell Rd. and 7th Avenue in central Phoenix. Even though McDowell Rd. is one of those 7-lane arterials, the scale and pace of this intersection has considerably slowed down thanks to the concentration of restaurants there with sidewalk cafes. Watching people sit, laugh, converse and enjoy themselves on the sidewalk introduces an entirely different pace to the busy street and helps slow traffic.

9. Make that turn lane into a landscaped raised median. A middle turn lane takes a car that is waiting to make a left turn out of the flow of traffic, which helps keep the pace of traffic fast. Replacing a middle turn lane would serve three purposes. One is that it would eliminate a lane, thereby effectively narrowing the street. The second is that it would reinsert the car waiting to make a left turn back into the traffic flow, thereby slowing down traffic. And the third is that a landscaped median with trees would in and of itself help slow traffic, as per point 4.

10. Add public art along the road that is visible from cars passing by. Public art, whether it's part of a bus stop, free standing markers (like the ones on Central in Sunnyslope), shading devices at crosswalks (like the ones on Camelback and 16th Street), marquee signs that span the street width (like the Melrose District sign) adds visual interest and a human scale back into the street. Some public art is designed to be noticed on by pedestrians, some can be seen while on a bicycle and some can be noticed from the speed of a car. Public art that is visible from a speeding car is most effective at slowing down traffic, as it catches the attention of a motorist, hopefully brings the motorist back into the present and makes her more aware of her surrounding and makes her slow down. Wall murals are also a great way to slow down traffic.

11. Put the parking lot in the back. When a huge sea of parking is visible from the street, it reinforces the idea that the city is built for cars and not for people. On the other hand, when businesses have front doors right on the sidewalks oriented towards pedestrians, like the businesses on the Miracle Mile on McDowell Road, it reintroduces the human scale to the road and this helps slow traffic.

12. Light Rail/Transit. One of the objections of adding the Light Rail on a street like Central Avenue was that it would slow traffic. And as predicted, it's considerably slowed traffic, and that's a good thing. The Light Rail moves at a relatively slow speed with frequent stops. This different pace, in addition to the elimination of one or two lanes helps slow car traffic. Plus, the Light Rail introduces people onto the road at the Light Rail stations. The presence of people on the road is a good way to slow down speeding cars.

Photo Credit: Photo by Strober (Own work) [CC-BY-SA-3.0], via Wikimedia Commons