Episode 12: Regression and traffic management

This week the topic was data analysis. We interviewed Judith Elgie from INRIX about her work as a data analyst, and how she uses computers to analyse and predict the movement of vehicles on the roads, to generate information about where traffic jams are and which roads are clear.

Interesting links:

• Introduction to regression lines by least squares, from m4ths.com
• Simple linear regression resources from Statstutor.ac.uk
• Traffic reporting, on Wikipedia
• Traffic information, on the UK Highways agency website

Puzzle: A lorry can travel from point A make a delivery at point B, 70 km away, in 1 hour. Today, however, after 30 minutes at the normal speed, the lorry is forced to stop for ten minutes. Resuming the journey, can the lorry arrive on time without breaking the 70mph speed limit?

Solution:

On a normal journey, the lorry travels 70km in 1 hour, which we can assume is a constant speed of 70km/h. Today, they travel at this speed for half an hour: 70km/h × 0.5h = 35km (this is also half the distance, as you would expect. The other 35 km must be travelled in 20 minutes, i.e. one third of an hour, so to calculate the speed needed we can divide 35 / (1/3) = 35 × 3 = 105 km/h. If we convert this to miles per hour, 105km/h is 65.3mph - so everything is legal.