In lieu of an abstract, here is a brief excerpt of the content:

• The Origins of the Section-Line Arterial Street Grid in Tucson, Arizona
• Joe Weber (bio)

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Aerial view of Tucson, looking east from downtown down Broadway, a section-line arterial street. Others can be seen to the north (left) and south. Source: Library of Congress, Carol M. Highsmith collection.

Many American cities have major streets spaced at 1-mile (1.6-kilometer) intervals in a regular grid, such as in Tucson, Arizona (Figure 1). Why is this so? The common answer is that it is due to the Public Land Survey (PLS), an 18th-century system devised to quickly survey the western frontier into 1-square-mile sections, with roads along section lines. Cities such as Tucson or Phoenix in Arizona; Joplin, Missouri; or Tuscaloosa, Alabama, are examples. But the assumption that the PLS directly gave rise to these roads is false: the PLS did not require section-line roads or even allow for their creation. They were instead a product of uneven and [End Page 149] changing state and county policies toward road creation. Nor were section lines necessary to create roads; a variety of laws as well as custom allowed their creation when and where needed. Further, these section-line arterials often appeared many decades after an area had been surveyed; the Public Land Survey might have no effect on a city’s street patterns for 70 years before section-line roads suddenly appear and become the city’s main roads. In other cities it might never have any influence on the street network. Why then do section-line roads appear as major arterials when and where they do? This paper will investigate this topic using the example of Tucson, Arizona, a classic western American arterial-grid city, using a variety of maps and legal records to trace the development of the city’s grid street network over 120 years.

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Principal meridians and baselines governing the United States Public Land Surveys. Source: Bureau of Land Management.

Where Do Roads Come From?

Identifying the origin of roads is a difficult task.¹ While well-known long-distance highways often have an abundant literature devoted to them, local roads and streets are likely to be poorly documented. They may also be created for different reasons in response to varying needs or initial conditions, such as roads that are established by use, those [End Page 150] created along property boundaries and reflect a particular land survey system, and those laid out in advance of settlement when a townsite is surveyed. For most of the United States the Public Land Survey (PLS) provides the land-division framework.

The Public Land Survey system was begun by an act of Congress in 1785 to allow the rapid settlement of new lands and to avoid the difficulties associated with the variety of survey methods that existed in the country.² The PLS was first implemented in Ohio in 1786 and was applied in every state north of the Ohio River and west of the Mississippi River (except Texas and Hawaii), and in several southern states (Figure 2).

Surveying for the system involves marking an initial point which allows a meridian and baseline to be established. These were used as the basis for surveying townships 6 miles (9.6 kilometers) to a side, which in turn were subdivided into 1-square-mile (259-hectare) sections. When the PLS began, land sales were for a minimum of a section (640 acres or 259 hectares), but this dropped to a quarter section of 160 acres (65 hectares) for homesteads and eventually as little as a quarter quarter section of 40 acres (16 hectares). In the West parcels were often obtained in much larger sizes due to aridity. The Desert Land Act of 1877 and the Stock Raising Homestead Act of 1916 allowed purchases of up to 640 acres (if irrigated, in the former case).³ These remained in effect until 1976 when the public domain was closed.

In 1855 the use of standard parallels was made mandatory in order to account for the curvature of the...

中文翻译：

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亚利桑那州图森市剖面线主干道网格的起源

以下是内容的简短摘录，以代替摘要：

• 亚利桑那州图森市剖面线主干道网格的起源
• 乔·韦伯（简介）

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从市中心沿着剖面线主干道百老汇向东看图森的鸟瞰图。其他可以在北（左）和南看到。资料来源：美国国会图书馆，卡罗尔·M·海史密斯 (Carol M. Highsmith) 收藏。

许多美国城市的主要街道均以 1 英里（1.6 公里）间隔呈规则网格分布，例如亚利桑那州图森市（图 1）。为什么会这样呢？常见的答案是，这是由于公共土地测量 (PLS)，这是一个 18 世纪的系统，旨在快速将西部边境调查成 1 平方英里的区域，并沿着剖面线铺设道路。亚利桑那州的图森或菲尼克斯等城市；密苏里州乔普林；或阿拉巴马州塔斯卡卢萨就是例子。但 PLS 直接产生这些道路的假设是错误的：PLS 不需要分段线道路，甚至不需要创建分段线道路。相反，它们是不均匀的产物[第 149 页完]改变州和县的道路建设政策。修建道路也不需要剖面线；各种法律和习俗允许它们在需要的时间和地点进行创建。此外，这些剖面线干道通常在某个区域被勘察数十年后才出现。在分段线道路突然出现并成为城市的主要道路之前的 70 年里，公共土地调查可能对城市的街道格局没有任何影响。在其他城市，它可能永远不会对街道网络产生任何影响。那么为什么分段线道路会在出现的时间和地点出现为主要干道呢？本文将以美国西部典型的网格状主干道城市亚利桑那州图森为例，利用各种地图和法律记录来追溯该城市网格街道网络120年来的发展。

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管理美国公共土地调查的主要经线和基线。资料来源：土地管理局。

道路从哪里来？_ _ _ _ _ _ _ _

确定道路的起源是一项艰巨的任务。¹虽然著名的长途高速公路往往有大量专门的文献，但当地的道路和街道可能记录很少。它们也可能因不同的原因而创建，以响应不同的需求或初始条件，例如根据使用而建立的道路、沿着财产边界创建的道路[结束第150页]并反映特定的土地调查系统，以及预先布置的道路调查城镇现场时的定居点。对于美国大部分地区，公共土地调查 (PLS) 提供了土地划分框架。

公共土地测量系统是根据 1785 年国会法案启动的，旨在允许快速定居新土地并避免与该国现有的各种测量方法相关的困难。² PLS 于 1786 年首次在俄亥俄州实施，并应用于俄亥俄河以北和密西西比河以西的每个州（德克萨斯州和夏威夷除外）以及南部的几个州（图 2）。

系统测量涉及标记一个初始点，以便建立子午线和基线。这些被用作测量边长 6 英里（9.6 公里）的乡镇的基础，这些乡镇又被细分为 1 平方英里（259 公顷）的部分。当 PLS 开始时，土地销售至少针对一个区域（640 英亩或 259 公顷），但用于宅基地的土地销售量下降到 1/4 区域（160 英亩（65 公顷）），最终减少到四分之一区域（40 英亩） （16公顷）。在西方，由于干旱，土地的尺寸通常要大得多。1877 年的《沙漠土地法案》和 1916 年的《牲畜饲养宅基地法案》允许购买最多 640 英亩的土地（如果是灌溉的，则为前一种情况）。³这些规定一直有效，直到 1976 年公共领域关闭为止。

1855 年，为了考虑曲线的曲率，强制使用标准纬线。