“Age Ain’t Nothing but a Number”, the title is catchy, but when it comes to pedestrian accidents it appears the Rhythm and Blues artist Aaliyah was wrong: age is more than just a number.

A recent publication by ProPublica takes an in-depth look at pedestrian accidents, analyzing how different speeds of the impacting vehicle can affect survival rates. One of the more striking findings in this report involves the correlation between survival rates and the age of the victim. Ultimately, it found that older victims faced a much greater risk of fatal injuries at much lower speeds than their younger counterparts.

Some examples of speeds and correlating risk of injury include:

• 25 mph. Many streets have a speed limit of 25 mph. When hit at this speed, a 30 year-old victim has a 7 percent risk of suffering from fatal injuries while a 70 year-old victim faces over triple this risk at 23 percent.
• 35 mph. Another notable jump occurs with accidents involving a car at this speed. In this accident, a 30 year-old victim would have a 22 percent risk of suffering fatal injuries, a 70 year-old victim faces more than double this risk, at 54 percent.
• 55 mph. At higher speeds, the rates begin to converge. A 30 year-old has an 82 percent chance of fatal injuries at this speed, a 70 year-old has a 96 percent risk.

This data provides more than just fodder for an interesting blog. It also supports some of the recent changes that are occurring in cities across the country.

Cities are beginning to drop average speed limits and such trends are supported by data like this. Even a drop from 30 mph to 25 mph can have profound effects on the severity of injuries in pedestrian accidents. According to the data from this study, on average a person is 70 percent more likely to be killed if hit by a vehicle traveling 30 mph than an accident with the same vehicle traveling 25 mph.