Some motorways have variable speed limits, with overhead information boards displaying the maximum speed allowed - Scottish Highers Physics - Question 4 - 2017

To comment on the system of variable speed limits on motorways, we can analyze the relationship defined by the equation: $\text{speed} = \text{frequency} \times \text{wavelength}$.

1. Understanding the Equation: This formula indicates that the speed of vehicles can be related to the frequency of some events (like the number of vehicles passing a point) and the wavelength, which, in this context, could represent the distance between vehicles.

   • When traffic is flowing well, there will be a higher frequency of vehicles, and the wavelength might be relatively short, translating into a higher speed limit.
   • Conversely, if congestion is present (lower frequency), the speed limit displayed would also decrease to ensure safety.

2. Practical Application: The overhead boards that display the maximum speed can dynamically adjust based on real-time data collected from sensors measuring traffic flow. This helps in reducing accidents and maintaining smooth traffic.

   • Moreover, if the calculated speed exceeds a certain limit, the displayed max speed ensures that vehicle speed does not lead to potential hazards.

3. Physics Principle: This system maintains a balance between the flow of traffic and safety, showcasing a good understanding of physics principles applied in a real-world scenario. By understanding that both frequency and wavelength will influence speed, the governing body can make data-driven decisions to improve road safety.

In summary, the implementation of this variable speed limit system effectively utilizes physics to manage traffic flow, enhancing safety and efficiency on motorways.