Thanks for contacting us via the support ticket method, but I thought I would also update this forum post as well!
As discussed, assigning each road a unique colour would be difficult but assigning a colour scheme through iteration is easier and less time-consuming.
For anyone else looking to accomplish a similar task, the best/quickest option would be to create a ‘Map Theme’ stylesheet and then use ‘Batch Generate Rules’ to create a rule for each road. To do this you should utilize the ‘Unique Values’ method and the colour ramp option in the ‘Visual Property Assignment’ to assign each road in the ‘roads layer’ a random colour. Then apply the batch-generated rules.
Alternatively, you can edit the original data to create an additional attribute and assign a repeating colour id e.g. (1 – 25) to each road. Then create a ‘Map Theme’ stylesheet that is based on the additional attribute and assign each road colour id its own colour. Then apply the rules. There will fewer rules needed since you are iterating through a set number of colour ids.
You can always submit a support ticket here for specific inquiries.