Optimize colours on the graph for colour blindness
I am almost completely unable to distinguish between the green and the orange dots on the graphs (although seeing their position relative to the yellow road is usually sufficient). The yellow and blue dots are fine.
Quotes from "Creating Maps for Color Blind People":
"Avoid using red and green together as this is the most common combination that the color blind cannot distinguish."
"Some good color combinations are: blues and yellows; magenta-violet and yellow-reds; blue, green, yellow sequences; and for diverging data where the mid values and extremes are both important, red, orange, yellow, light blue and dark blue (center the yellow-blue transition on the pivot point in your data)."
"Add tooltips to colored items so that users can hover over top and find out exactly what they represent."
"If the look and feel of the map you are making is very important to you, consider adding a custom color blind friendly map that can be accessed by clicking on a link. That way both types of users have a map they can work with."
http://apollomapping.com/blog/g-faq-creating-maps-color-blind-people-part-ii

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Karlson Pfannschmidt commented
I would suggest the option to customize the graph colors (maybe in the advanced settings to avoid clutter).
That way not only color vision deficient people can choose the most discernible colors.
But every user can customize the colors to their liking.