Answer: The total number of vehicles in the bar graph does not add up to 30.
The spacing between the bars should be equal.
It would be helpful to put the number of each type at the top of its bar.
It may be useful to give the location and time/date of the observation in the title of the graph.
Step-by-step explanation: The total 12 + 8 + 6 = 26.
My other observations would depend on the purpose of the graph. Many people use color to make the graph more visually appealing.