The two areas in the trial covered around 500 streets from the south and east of Bristol. The project aimed to test whether the success achieved in Portsmouth could be replicated on Bristol streets.
Their findings demonstrated that: "20mph limits, if introduced with careful community engagement, and underpinned by excellent communication and driver education, can help bring about shifts in choice of travel mode and support local aspirations." - 20mph Monitoring Report 
Some of the headline findings are:
- 65% of roads saw a reduction in mean speeds
- 18 roads no longer saw average speeds above 24mph
- The average reduction in mean average speed across roads in the southern area was 1.4mph, and eastern area was 0.9mph
- The mean average speed across all roads has dropped to 23mph and under between 7am through to 7pm
- Increase in counts for cycling range from 4% increase to 37% increase.
- Pedal cycle casualties in the southern area have fallen by 3 in the sameperiod but remained constant in the eastern area
- Pedestrian casualties have remained constant in both areas.
- 89% of residents supported 20 mph on all residential streets
- 56% of residents supported 20mph on ‘main’ roads
This is one of the first major studies to reveal the impact on people's cycling and walking as a result of reducing speeds. That's an important finding because it gives an even stronger argument that 20mph is good for health and the environment. The Bristol study has also revealed that support increased after implementation.