The BCS examinees were requested to leave for exam venues with sufficient time in hand so that they do not get caught up in traffic.
DMP's traffic division has offered apologies for the inconvenience.
As many as 475,000 job seekers have applied to sit for the 41st BCS exams against 2,166 posts. The preliminary exams are scheduled to be held in eight divisional cities.
Bangladesh Public Service Commission on 13 January announced the exam date.
But education minister Dipu Moni on 22 February said that the exam would be postponed. However, the PSC on 3 March decided to organise the 41st BCS exam on 19 March.
The High Court on 16 March dismissed a writ petition seeking postponement of the preliminary examination. It directed the PSC to conduct the examination in compliance with the health rules.
Following the directive, the PSC circulated an 11-point guideline in this regard the same day.
Students will take part in the two-hour preliminary examination from 10am to 12pm in Dhaka, Chattogram, Rajshahi, Khulna, Barishal, Sylhet, Rangpur and Mymensingh examination centres.