The present invention relates to a cost effective and industrially advantageous process for the preparation of imipenem of high purity comprising the steps of treating an aqueous solution containing imipenem with an organic solvent, wherein the imipenem is not lyophilized; and isolating the pure crystalline imipenem monohydrate from the reaction mixture thereof. The vehicle position calculation apparatus has a vehicle position measuring section measuring a vehicle position, a road data supply section supplying road geometrical data including a line segment and a closed region correlated with a road on a map, and a vehicle position correcting section correcting the vehicle position on the map by using the road geometrical data. The position status detector generates status information by detecting a position status of the hand-held voice transceiver. The risk is controlled by providing closer scrutiny of the identity of the test entity prior to distributing a test enabled permission to the test entity, providing expiration times associated with the test enabled permissions, and limiting the number of test enabled permissions distributed.