To make the customer aware of age of the current lighting and thereby opening them up to consider an upgrade (now). Since older installations are often less energy efficient, application bundle is a solution which brings up to 65% energy savings.
Was it recently (or ever) checked to meet lighting standards?
If it was never checked (or checked a long ago) there is a chance it does not (or no longer) meet the minimum requirements according to standards. If the values are not meeting the minimum, this can have impact on safety in the car park. This is an argument for an upgrade.
Is the traffic constant throughout the day?
To establish if the sensors would make a difference (energy saving). If the traffic indeed differs throughout
the day or night, sensors are an important part of the solution.