D1 is a vehicle fleet management web application built for a Tunisian transport/tourism company. It tracks the full lifecycle of each vehicle: registration, maintenance schedules, fuel consumption, leasing payments, insurance, spare parts inventory, and driver assignments. The system automates recurring expense tracking with status alerts (overdue, warning, paid), generates cost and profit reports per vehicle, and integrates with a separate tourism database for income/tariff calculations. Built with PHP, MySQL, and Bootstrap 5, it reduced manual tracking errors and gave management real-time.