Results of Cascade Road Diet: Background Before data set was - - PowerPoint PPT Presentation

• “Before” data set was collected on 1/18/18, and “After” data collected on 11/27/18
• Cascade was re-striped on 8/15/18
• On 11/27/18, the total traffic volume through ONE had increased to 32,566

(increased by 1,585)

• Data show that this increase was a normal 5% fluctuation and not causally related to

the road diet

• Traffic volume on Nevada and Cascade typically vary proportionally
• Historically, when the total traffic volume through the ONE rises and falls, Nevada and

Cascade have also risen and fallen by an amount that is proportional to their size

• This is shown in city traffic counts, going back to 1997
• Nevada carries 44%, so in 2018, it should have increased by about 1,585 * 0.44 = 697 vpd
• Cascade carries 29%, so in 2018, it should have increased by about 1,585 * 0.29 = 460 vpd

Results of Cascade Road Diet: Background

1

Cascade Nevada Weber Wahstach Totals 1/18/18 ADT 8,882 13,665 3,340 5,094 30,981 Percentage 29% 44% 11% 16% 100% This is the Total Traffic Volume Distribution Through ONE in January of 2018

• Traffic Volume
• Change in the total number of vehicles is marginal
• Small increase north of Fontanero, and small decrease south
• This occurred during substantial increase in traffic volume across the ONE
• 1,585 * 0.29 = 460 vehicles should have been added : 460 + 68 = 528 were diverted
• Speed Distribution
• Shifted approx. 5 mph to lower speed
• Before Road Diet, there were 970 vehicles above 45 mph, and 62 over 55 mph
• After Road Diet, there were 92 over 45 mph and 0 over 55
• Still, nearly everyone is above the speed limit – they are not badly inconvenienced

Results of Cascade Road Diet: Cascade

2 Location Before Road Diet After Road Diet Change South of Fontanero 8,882 8,814

• 68

Cascade Traffic Volume (Vehicles per Day)

• 500

500 1000 1500 2000 2500 3000 3500 4000 4500 10 20 30 40 50 60 70

Number of Cars Speed (mph)

Speed Changes on Cascade after Road Diet

Cascade S Before Cascade S After

Speed Limit

On Cascade (south of Fontanero), there were 68 fewer vehicles after the road diet, despite substantial growth elsewhere through the Old north End

This is fantastic!

• Traffic Volume
• Substantial growth in the number of vehicles
• 8.0% more south of Fontanero
• This is well beyond the measurement uncertainty
• We conclude that there has been significant diversion to Nevada
• While Nevada typically carries 44% of the N/S burden, it took on 72% of the growth
• Expect growth to be 1,585 * 0.44 = 697 vehicles, 1,091 – 697 = 394 extra vehicles

beyond expected growth

• Speed Distribution
• Very few cars are actually going slower
• The lower mean speed can be accounted for by increase in traffic volume
• Speed limit reduction (from 35 to 30 mph) had no measurable effect
• Distribution is a bit broader, which means cars interact more (some slow, some fast)
• This is a more dangerous situation

Results of Cascade Road Diet: Nevada

3 Location Before Road Diet After Road Diet Change South of Fontanero 13,665 14,756 +1,091

Nevada Traffic Volume (Vehicles per Day)

• 1000

1000 2000 3000 4000 5000 6000 7000 10 20 30 40 50 60 70

Number of Cars Speed (mph)

Speed Changes on Nevada after Road Diet

Nevada N before Nevada N After

• Traffic Volume
• Changes on Wood & Tejon (adjacent to Cascade) are statistically insignificant
• This conclusively demonstrates that Cascade road diet does not divert

cars to two-lane roads

• Wahsatch (like Nevada) took on more than its proportional share (427 vs 253)

Results of Cascade Road Diet: Other North/South Streets

4

Location Before Road Diet After Road Diet Change Wood 547 554 +7 Tejon 598 552

• 46

Weber 3,340 3,476 +136 Wahsatch 5,093 5,520 +427

Traffic Volume (Vehicles per Day)