Most local codes specify different heights between the back and side yard and front yard fences. There may be variation between residential zones. Generally there is also an easement for municipal services so the property line is not adjacent to the street; it's set back to allow for the easement. Lots located at an intersection or an alley have to allow for visibility; codes outline a sight triangle that the fence must respect.
Ensure that the fence accurately follows the property line and doesn't overlap. Look for pins or markers at the corners of the lot, and establish a line that connects them. A survey plan is helpful, as is calling a surveyor to verify the location of the property line. A corner lot where streets intersect needs special attention in layout.
For corner lots there is usually a regulation to maintain an unobstructed view for pedestrians and vehicles. Measured a certain distance each way from the corner, the so-called sight triangle has to remain free of any element high enough to impede the vision of a driver or pedestrian. The restriction includes planting as well as fences; plants or hedges must be kept within the height limit. Both frontages are considered the front yard of a corner lot.
Front yard fence height is restricted for safety, aesthetic and social reasons. Regulations establish a definition for what's considered the front yard. For example, the fence regulations may define the front yard as the distance between the front property line and the nearest building wall, or front setback line, whichever is shortest. The higher fence can start at the wall of the house and extend across the yard. Though this fence is seen from the front, it's not a front yard fence.