The reason why transportation credit cards will prompt you for large purchases when you spend more than 1,500 yuan is that transportation credit cards have a consumption warning function. According to the official website of Bank of Communications, when your credit card consumption amount reaches a certain amount, an early warning reminder will be automatically triggered to ensure the safety of your credit card use. Generally speaking, the early warning amount of Bank of Communications credit card is set to 1,500 yuan. Above, when your consumption amount reaches or exceeds this amount, a text message or APP push reminder will be sent to you.