Question about TTI

[RobinLu1209]

Hi, I am very glad DiDi can provide such a good dataset, but I have some question about TTI.

• First, how can you know the free flow speed on every road? Do you provide this free flow speed in your dataset?
• Secondly, what does the set S mean? Is it means if I want to calculate the TTI of the whole city, I will put every road in this S? And if I only want to calculate TTI of every road, the size of set is 1?
• Last but not least, I have applied for the dataset on tht website(https://outreach.didichuxing.com/app-vue/TTI?id=1003) for quite a long time, but I still have no response, and wish I will get the dataset soon.

Thanks for your great help!