TR-Speedo is the speedometer app for drivers of the brand Triumph.
The design is inspired by the speedometer of a Triumph.
This app does not always show the true speed. Therefore set up your speed for a suitable device. Normally this will be the speedometer of your vehicle.
The speed and thus the mileage is taken over by the GPS receiver of your iPhone. The accuracy is primarily dependent on the quality of the GPS satellite reception conditions. This is also dependent on the surroundings (narrowness wooded mountain valley or on the dike along the coast) and the weather (a clear sky = good reception, rain, snow, and thick clouds = bad reception). But other factors, such as the number of simultaneously used apps can affect the accuracy.
Even at standstill, the iPhone recorded a little movement. Due to all these factors, the "measurements" which are found out for acceleration and braking distance are in principle also inaccurate.