The DAB's Elizabeth Quat asked whether the government plans to expand joint border clearance to more ports for greater efficiency. "It's easier to adopt such arrangements at newly built or redeveloped checkpoints, because they are newly designed. At older ports, say in Lo Wu, the design is not for such border clearance arrangements. There are more space constraints," Tang said in response. But he said officials have been looking at adopting the clearance method at bigger border points such as the Liantang/Heung Yuen Wai port. Meanwhile, unionist lawmaker Bill Tang proposed allowing Shenzhen vehicles to come to Hong Kong on Sundays, saying such drivers should be middle class and that their spending would boost the local economy. Tang said in response that officials have plans to allow mainland passengers using the airport to park their vehicles there. But he said further study would be needed as to whether more cars can be allowed into the SAR.