Smart cities demand resources for rich immersive sensing, ubiquitous communications, powerful computing, large storage, and high intelligence (SCCSI) to support various kinds of applications, such as public safety, connected and autonomous driving, smart and connected health, and smart living. At the same time, it is widely recognized that vehicles such as autonomous cars, equipped with significantly powerful SCCSI capabilities, will become ubiquitous in future smart cities. By observing the convergence of these two trends, this article advocates the use of vehicles to build a cost-effective service network, called the Vehicle as a Service (VaaS) paradigm, where vehicles empowered with SCCSI capability form a web of mobile servers and communicators to provide SCCSI services in smart cities. Towards this direction, we first examine the potential use cases in smart cities and possible upgrades required for the transition from traditional vehicular ad hoc networks (VANETs) to VaaS. Then, we will introduce the system architecture of the VaaS paradigm and discuss how it can provide SCCSI services in future smart cities, respectively. At last, we identify the open problems of this paradigm and future research directions, including architectural design, service provisioning, incentive design, and security & privacy. We expect that this paper paves the way towards developing an economically effective and sustainable approach for building smart cities.

翻译：智慧城市需要丰富的沉浸式感知、泛在通信、强大计算、大容量存储与高级智能（SCCSI）资源，以支持公共安全、网联自动驾驶、智慧医疗及智慧生活等多类应用。同时，自动驾驶汽车等配备强大SCCSI能力的车辆，未来将在智慧城市中无处不在。基于这两大趋势的融合，本文倡导利用车辆构建经济高效的服务网络，即车辆即服务（VaaS）范式——由具备SCCSI能力的车辆构成移动服务器与通信器网络，为智慧城市提供SCCSI服务。为此，我们首先分析了智慧城市中的潜在用例，以及从传统车载自组织网络（VANET）向VaaS转型所需的关键升级。随后，分别介绍VaaS范式的系统架构及其在智慧城市中提供SCCSI服务的方式。最后，提出了该范式的开放性问题与未来研究方向，包括架构设计、服务提供、激励机制设计及安全与隐私保护。本文预期为构建智慧城市的经济高效且可持续的发展路径奠定基础。