Four of the ten worst US traffic corridors are in New York City and three in Chicago as shown in this bubble chart. The Cross Bronx Expressway (I-95 Eastbound) is the worst corridor. Inrix estimates that it causes 118 hours of delay per year for commuters. The average speed is about 10 mph during the morning rush hour and 15 mph during the afternoon rush. Two New York City streets--34 and 42--had the slowest rush hour traffic. They both averaged about 5 mph in the morning and afternoon rush.
Three Chicago interstates also made the top 10. I-90 Souhthbound, I90/94 Southbound and I-290 Eastbound caused 66, 98 and 89 hours of delay for their commuters. Their average speeds were a bit higher, averaging between 25 and 35 mph during rush hours.
The top ten is rounded out by one Los Angeles, one Pittsburgh, and one Boston interstate, and Brooklyn's Belt Parkway. Given Los Angeles' reputation for traffic jams, it seems to be underrepresented.
How I Created the Bubble Chart
The bubble chart shows three traffic-related measures--morning rush hour speed, afternoon rush hour speed, and total hours delayed. The last provides an overall magnitude of the traffic in each corridor and was used to rank the top 10. The bubble chart allows you to see how slow or fast you can drive in each corridor during peak commute times. Some of the delays are caused by very slow traffic (e.g., 34 and 42 St) and some by a high volume of cars moving slower than they could (e.g., Belt Parkway). The Cross Bronx has both, making it the worst corridor.
Here are the steps I took to create the chart:
- enter the data from the table in the Inrix report into the Mekko Graphics Data Editor
- use the x and y columns for to specify AM and PM speed in mph and the bubble size for hours delay
- use the group column in the Data Editor to specify the city
- adjust the x and y axis maximums and tick intervals to get the bubbles nicely spaced in the chart
- set the colors for each group (city) and add the legend
- move the bubble labels to eliminate overlap and improve readability
As a tip, I recommend moving bubble labels as the last step. If your data or axes change, you might have to move the labels again.
Take This Chart and Make It Your Own
Here are some other posts that may interest you: