Sometimes we need to do a bulk alteration in several segments, like to change max-speed, directions and so. Although it is possible to select all the street, sometimes, we don't need to change all the segments in the street.
Also, if a person has some mobility disability or dificulties, it is common they lost their selection of several segments because either clicked in a wrong place or not hold the ctrl key.
The suggestion is either a creation of a 'Selection mode' that can be activated and allows the user to click in the desired elemnts or a checkbox like UI element in each segment that holds the selection across the map navigation.