1. The alignment should be laid out so that approaches are on a tangent which is at least 400 feet long, 200 feet on each side of the crossing. The angle that the highway makes with the railroad should not be less than 60 degrees. The grade of the approaches should not be greater than 6 per cent, and there should be a portion level or nearly so for a distance of not less than 100 feet on each side of the crossing.

2. On the highway within 200 feet of the railroad, on each side, traffic should have a clear view of approaching trains for a distance of 1,000 feet. (See Rule 5.)

3. The width of the planked crossing shall not be less than 24 feet, measured at right angles to the center line of the highway. The ends of the pavement should be protected by an edging of stone or concrete placed at a sufficient distance from the ends of the ties to allow for replacing them.

4. A standard danger sign should be placed at each side of the crossing along the highway in a prominent location at least 400 feet from the crossing.

5. When the view of the railroad either way, as required in 2, is less than 1,000 feet, or when there is a great deal of traffic on either the highway or railroad, or when vision may be blocked by cars or trains as in the case of a railroad with two or more tracks, a flagman should be employed to warn highway traffic.

The New York State highway department's rules for the elimination of grade crossings are as follows:

1. Subways shall have a clear head-room of not less than 13 feet and a clear width between abutments of not less than 26 feet. The approaches when in a cut shall have a minimum width of 28 feet between bottoms of slope. When a highway passes over a railroad the clear height over said railroad shall be not less than 21 feet and the approaches when on embankment shall be not less than 28 feet wide across the shoulders.

2. The alignment and grade of approaches shall be such that traffic at any point within the limits of the elimination will be able to see that approaching it for a distance of 300 feet. The maximum allowable grade shall be 6 per cent.

3. Bridges carrying railroads over highways shall be of a solid-floor, ballasted type. Drainage of such floors shall be such that water will not drop upon the roadway. Bridges_carrying highways over railroads shall have solid concrete floors with a minimum width of roadway of 18 feet.

4. When an elimination is made on a highway already improved, the pavement shall be of the same type as the existing pavement. If the highway is not improved the pavement shall be the same as that contemplated.

5. Subways shall be drained in a thoroughly satisfactory

manner.

6. The limits of an elimination shall be taken as the points of intersection of the approach grades of the elimination with the grade of the existing highway.

REGULATIONS OF THE CALIFORNIA HIGHWAY COMMISSION REGARDING

SURVEYS AND PLANS1

Part 1. Surveys

(a) Note Books.-Survey note books will be furnished to the chief of party by the Division engineer. No survey note book other than the standard book so furnished shall be used, and the use of loose sheets is prohibited. The notes placed therein shall be the "original" notes of the survey and shall not be copied from sheets or from other books.

The standard book shall be used for alignment, topography and levels, and for all other information which the survey parties are required to secure; all notes shall begin at the bottom of the page and read upward.

On beginning a survey the chief of party shall see that a proper entry of the Division, county and route, is made upon the label pasted to the inside of the front cover of the note book.

Attached to the back cover of each book are several pages showing the "standards" required in all surveys. All survey notes shall conform in so far as possible to such "standards" to the end that all surveys and the manner of taking the notes thereof shall be uniform throughout the work.

At the beginning of each day's work the following data shall be entered in the book: Date; weather conditions; names of members of party and duties of each.

When no notes are taken on a working day or portion of a day, the date shall be entered and the reason for the loss of time shall be stated clearly and concisely.

All survey and other notes shall be suitably indexed on the first ruled page of the note book.

Every day at the close of the work the notes shall be copied neatly upon specially printed sheets furnished by the division engineer and numbered consecutively, and after careful checking such sheets shall be forthwith forwarded to the division engineer.

No note book shall contain notes relating to more than one route or to more than one county.

1 From Austin B. Fletcher, State Highway Engineer of California.

(b) Alignment Notes.-The base line of the survey shall be referred to the true meridian, which shall be determined by observation on polaris. The chief of party before beginning a survey shall procure all tables and other data needed for such determination and observations shall be made from time to time to ensure the accuracy of the work. The line shall also be checked by magnetic bearings taken at each transit point. All angles in the base line shall be azimuth angles read from the back sight and repeated with the telescope reversed.

Complete traverses shall be run in all surveys and computed in the field. If the error of closure exceeds 1: 5000 the division engineer shall be notified and the party shall not move camp until he has authorized such moving. The closures shall be completed and computed in such lengths as the division engineer shall prescribe.

The base line shall be as nearly as may be in the center of the proposed road. When it is apparent that a tangent base line will not follow the approximate center of the proposed road, a curve of suitable radius shall be run. Curves shall be measured by computing the length of the arc and not by chords.

If the survey follows an existing road, wire nails not less than 5 inches in length shall be driven flush with the traveled way at all angle points in the base line, at the beginning and ending of all curves and on long tangents at intervals not exceeding 1000 feet.

When the base line does not follow a traveled way or when the roadway is so soft that nails will not hold their position, wooden stakes driven flush with the ground shall be used and the transit point indicated thereon by a small nail.

All transit points shall be properly referenced as provided under the caption "Stakes."

Stations shall be established every 100 feet on the base line and indicated by short wire nails driven through bits of red cloth into the ground to serve as temporary markers during the survey. The stations and half stations shall be also permanently marked by stakes set on both sides of the proposed road sufficiently far removed from the base line to prevent their being disturbed during the building of the road.

(c) Stakes. All stakes which are to be used for establishing grades shall be made from 2 x 3 inch scantling, from 24 to 30 inches in length, laid flat and sawed diagonally into two wedges, with the sharp ends approximately inch thick. The lumber from which the stakes are made shall be sound, reasonably free from knots, and planed on all sides. These stakes shall be driven into the ground to about one-half of their length with the 2-inch face parallel to the base line. On the right side of the road the

station number shall be marked plainly on the side of the stake facing Station O, and on the opposite side of this stake shall be marked to the nearest tenth, the offset from the base line. The face toward the road must be reserved for marking during construction. On the left hand side of the road, the offset from the base line shall be marked on the side of the stake facing Station O and the station number on the opposite side.

All stakes used to mark monuments and for transit points shall be wedge shaped, not less than 1 foot in length nor less than } x 2-inch at the top. Such stakes shall be driven flush with the ground unless they are so located as not to endanger the traveling public. Short nails driven into the tops of these stakes shall indicate the monument and transit points.

All monument and transit points shall be referenced by three ties to natural objects or, if such do not exist, to stakes, as shown by the "standards" at the back of the note book.

(d) Topography.-All objects, such as houses, barns, fences, gates, field entrances, trees, telephone and telegraph poles, power lines, railroad and railway tracks, within a distance of 150 feet on either side of the base line shall be located by offsets from the base line and recorded in considerable detail, and the limits of the "traveled way" on all existing roads shall be indicated. Separate sketches, with levels and dimensions of all essential features, shall be made in the note book of all bridges, large culverts and other appurtenances of the road, and plainly referenced in the topography notes.

The azimuth from the back sight to the boundary lines of all incorporated cities and of all counties shall be ascertained and recorded. The azimuth of the boundary lines of all entering and intersecting highways, of township lines, and of division lines between property holdings shall be ascertained and recorded with reasonable accuracy, and when feasible the names of the owners of property abutting on the proposed road shall be recorded.

When it is desirable to locate topographic features from a sub-tangent, the station will be measured from the nearest end of the curve.

(e) Levels-Whenever there is a known government bench within 3 miles of the survey, the datum plane of such bench shall be adopted for the work. If no such bench is available, a datum plane shall be assumed at such an elevation as will be low for all parts of the survey.

Benches shall be established during the progress of the work at each end of the survey, at city and county lines, and at other convenient points not more than 1000 feet apart, and at shorter intervals on grades.